KR20080068102A - Positioning device, positioning control method, positioning control program and recording medium - Google Patents

Abstract

The positioning device 1020 includes a phase calculating unit that calculates a current phase of the positioning base code by performing correlation processing between the predetermined replica positioning base code and the positioning base code from a predetermined source, A prediction phase calculator for calculating a prediction phase when the current phase is predicted based on the Doppler shift of the frequency of the radio wave carrying the positioning base code, the elapsed time from the last positioning time, and the calculated current phase It has a phase difference evaluation part which determines whether the phase difference of a prediction phase is in the predetermined phase difference range, and the positioning part which positions a present position using the phase within a phase difference tolerance range.

Description

Positioning device, positioning control method, positioning control program and recording medium {GLOBAL POSITIONING DEVICE, GLOBAL POSITIONING CONTROL METHOD, GLOBAL POSITIONING CONTROL PROGRAM, AND RECORDING MEDIUM}

The present invention relates to a positioning device, a positioning control method, a positioning control program, and a recording medium using radio waves from a source.

Background Art Conventionally, a positioning system for positioning a current position of a GPS receiver using a GPS (Global Positioning System), which is a satellite navigation system, has been put into practical use.

The GPS receiver transmits radio waves from GPS satellites (hereinafter, satellite radio waves) based on navigation messages indicating the orbit of the GPS satellites (including rough satellite orbit information: almanac, precision satellite orbit information: epimeris, etc.). A C / A (Clear and Acquision or Coarse and Access) code, which is one of the pseudo noise codes (hereinafter referred to as PN (Psuedo random noise code) codes), is received. The C / A code is a code on which positioning is based.

The GPS receiver determines which GPS satellite the C / A code originates from, and then, based on the phase (code phase) of the C / A code, for example, the distance between the GPS satellite and the GPS receiver (pseudo distance). ) Is calculated. The GPS receiver is configured to position the GPS receiver based on a pseudo distance with respect to three or more GPS satellites and a position on the satellite orbit of each GPS satellite. For example, a C / A code has a bit rate of 1.023 Mbps and a code length of 1,023 chips. Therefore, it can be considered that the C / A code runs side by side every 300 km (km), which is a distance in which radio waves propagate between one millisecond (ms). Therefore, the pseudo distance can be calculated by calculating how many C / A codes are between the GPS satellites and the GPS receiver from the position of the GPS satellites on the satellite orbit and the outline position of the GPS receiver. More specifically, if one cycle (1,023 chips) of the C / A code is calculated (an integer part of the C / A code), and the phase of the C / A code (the singular part of the C / A code) is specified, , The pseudo distance can be calculated. Here, the integer part of the C / A code can be estimated if the approximate position of the GPS receiver is within a certain precision, for example, within 150 km. For this reason, the GPS receiver can calculate the pseudo distance by specifying the phase of the C / A code.

The GPS receiver, for example, takes the correlation between the received C / A code and the replica C / A code generated inside the GPS receiver and integrates it, and the phase of the C / A code when the correlation integration value reaches a constant level. Specifies. At this time, the GPS receiver performs correlation processing while shifting the phase and frequency of the replica C / A code.

By the way, when the radio wave strength of satellite radio waves carrying a C / A code is weak, sufficient signal strength cannot be obtained, and it becomes difficult to specify the phase of the C / A code.

On the other hand, the technique which combines the result of processing the segment of a received signal continuously and coherently (synchronously) until the limit signal noise ratio (SNR) is achieved is proposed (for example, patent document 1). ).

[Patent Document 1: Japanese Patent Publication No. 2004-501352]

However, since the GPS satellites and the GPS receiver move relatively, the arrival frequency of the satellite radio waves reaching the GPS receiver changes due to the Doppler shift.

Here, when the signal strength is weak, it may be difficult to synchronize the synchronization frequency on the GPS receiver side to the continuously changing arrival frequency.

When the synchronization frequency on the GPS receiver side is different from the arrival frequency, even if the correlation integration value reaches a constant level, the accuracy of the phase of the C / A code at that time deteriorates. For this reason, when positioning using the phase, there exists a problem that the precision of a positioning position may deteriorate.

Accordingly, the present invention provides a positioning device, a method of controlling the positioning device, a program thereof, and a recording medium which can be accurately positioned after verifying the accuracy of the phase of the positioning base code under a weak electric field having a weak radio wave strength. For the purpose of

One aspect of the present invention is a phase calculating section that performs correlation processing between a predetermined replica positioning base code and a positioning base code from a predetermined source, and calculates a current phase of the positioning base code; A prediction phase calculator for calculating a prediction phase when the current phase is predicted based on a phase, a Doppler shift of the frequency of the radio wave carrying the positioning base code, and the elapsed time from the last positioning time, and the phase A current position using a phase difference evaluation unit that determines whether or not the phase difference between the phase and the predicted phase calculated by the calculation unit is within a predetermined phase difference tolerance range, and the phase corresponding to the phase difference within the phase difference tolerance range Relates to a positioning device having a positioning unit for positioning.

According to this, since a positioning device has a phase difference evaluation part, it can judge whether a phase difference exists in the said phase difference tolerance range. That is, the positioning device can verify the accuracy of the phase.

Moreover, since a positioning device has a positioning part, it can position a present position using the phase corresponding to the phase difference within a phase difference tolerance range.

For this reason, the positioning device can perform positioning with high accuracy after verifying the accuracy of the phase of the positioning basic code under a weak electric field having a weak radio wave strength.

Moreover, in 1 aspect of this invention, the said phase calculating part calculates the said phase using a some frequency series, and the said phase difference evaluation part is the frequency series with the largest signal strength of the said positioning base code among the said plurality of frequency sequences. You may comprise the positioning apparatus which determines whether the phase difference of the said phase computed using and the said prediction phase exists in the said phase difference tolerance range.

According to this, the phase calculation part is a structure which calculates a phase using several frequency series. The precision of the reception frequency of one frequency series will be higher than the precision of the reception frequency of another frequency series. For this reason, the positioning device is likely to be able to calculate the phase at a reception frequency with high accuracy.

Here, in general, it can be estimated that the accuracy of the reception frequency in the frequency series with the largest signal strength is the highest. Therefore, in general, it can be estimated that the phase calculated in the frequency series having the largest signal strength is higher in accuracy than the phases of other frequency series.

However, especially under the weak electric field, the accuracy of the reception frequency in the frequency series with the largest signal strength is not limited to the highest reliability.

In this regard, since the accuracy of the phase calculated in the frequency series having the largest signal strength of the positioning base code can be verified and excluded from the positioning, calculating a poor positioning position under a weak electric field with a weak radio wave strength You can prevent it.

In one aspect of the present invention, the phase calculating unit performs the correlation processing of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source to set the phase of the positioning base code. The positioning unit includes a phase selection unit in which the phase difference selects the minimum phase for each of the source sources among the phases corresponding to the phase difference within the phase difference allowable range, and sets the phase as the selection phase, and the signal strength of the selection phase is The selection phase first evaluation unit for judging whether or not the maximum value and the phase in the frequency series to which the selection phase belongs are within a prescribed number of times specified in the predetermined range of allowable phase differences Has a selection phase second evaluator for judging and determining by the selection phase first evaluator When a result and / or the determination result by the said selection phase 2nd evaluation part is affirmative, you may comprise the positioning apparatus which positions the present position using the said selection phase.

According to this, since a positioning device has a phase difference evaluation part, it can judge whether a phase difference exists in a phase difference tolerance range. That is, the positioning device can verify the accuracy of the phase.

Moreover, since the positioning device has a phase selector, it is possible to calculate the selection phase for each source. Since the selected phase is a phase having a minimum phase difference, the selection phase is higher in accuracy than the phases of other frequency series.

Since the positioning device further has a selection phase first evaluation unit, it is possible to determine whether or not the signal strength of the selection phase is maximum. If the signal strength of the selection phase is maximum, it can be considered that the selection phase is guaranteed to be higher in accuracy than other phases. And since a positioning device has a positioning part, when the determination result by a selection phase 1st evaluation part is affirmative, it can position a current position using a selection phase.

For this reason, the positioning device can perform positioning with high accuracy after verifying the accuracy of the phase of the positioning basic code under a weak electric field having a weak radio wave strength.

Here, especially under a weak electric field, the signal strength of the phase whose phase difference is minimum cannot be limited to the maximum. That is, although the precision of the selection phase is higher than other phases, the signal strength may not be maximum. For this reason, even when the signal strength is not maximum, it is preferable to use the selection phase for positioning as long as the accuracy of the selection phase can be confirmed.

In this respect, since the positioning device has a selection phase second evaluation unit, when the number of times in the frequency series to which the selection phase belongs is within the specified number of times, the selection phase is used to select the present phase. Position can be located.

For this reason, even if the determination result by a selection phase 1st evaluation part is negative, a positioning device can perform positioning using a phase with high precision.

Moreover, in 1 aspect of this invention, the said prediction phase calculation part is the said phase at the time of last positioning, and comprises the positioning apparatus which calculates the said prediction phase using the said phase at the time of completion of the said correlation process. You may also

In the process of correlation processing, since the completion time, for example, SNR (signal-to-noise ratio) improves than the start of correlation processing, and positioning base codes can be clearly distinguished from noise, the phase accuracy is high.

This point and the prediction phase calculation part are the said phases at the time of last positioning, and since it is the structure which calculates a prediction phase using the phase at the completion of a correlation process, it calculates the said prediction phase with high precision. can do.

In other words, the positioning device can calculate a prediction phase with a high precision as a basis for positioning with high accuracy.

Moreover, in 1 aspect of this invention, the reception frequency specification part which specifies the reception frequency at the time of receiving the said radio wave carrying the positioning basic code, and the frequency difference between the said reception frequency at the time of last positioning, and the said current reception frequency are previously prescribed | regulated. A positioning device having a frequency difference evaluating unit for judging whether or not it is within one frequency difference allowable range and a phase exclusion unit for excluding a phase of the positioning base code corresponding to the frequency difference outside the frequency difference allowable range from positioning do.

According to this, since a positioning apparatus has a phase exclusion part, the phase of the positioning basic code corresponding to the frequency difference outside the frequency difference tolerance range can be excluded from positioning.

This means that the positioning device can verify not only the precision of the phase of the positioning base code but also the precision of the reception frequency when the phase is calculated. The higher the accuracy of the reception frequency, the higher the phase accuracy.

For this reason, the positioning device can perform positioning with higher accuracy after verifying the accuracy of the phase of the positioning basic code under a weak electric field having a weak radio wave strength.

Moreover, in 1 aspect of this invention, the reception frequency specification part which specifies the reception frequency at the time of receiving the said radio wave carrying the positioning basic code, and the frequency difference between the said reception frequency at the time of last positioning, and the said current reception frequency are previously prescribed | regulated. A frequency difference evaluator for determining whether the frequency difference is within an allowable range,

It has a phase exclusion part which excludes the phase of the said positioning basic code corresponding to the said frequency difference other than the said frequency difference tolerance range from positioning, The said frequency series are mutually separated by the frequency interval prescribed | prescribed mutually, The said frequency difference tolerance range You may comprise the positioning device prescribed | regulated by the threshold value less than the said frequency interval.

According to this, when the said frequency series with the largest signal strength is changed, the phase at that time can be excluded from positioning. This means that the frequency series having the largest signal strength is continuous as a condition for using the phase for positioning.

For this reason, since the phase computed in the frequency series which best tracks the Doppler shift of the frequency of the radio wave which reaches a positioning device can be used for positioning, positioning is performed more precisely under the weak electric field with a weak radio wave intensity. can do.

Moreover, in 1 aspect of this invention, it has a phase difference tolerance range determination part which determines the said phase difference tolerance range based on the reception state of the said positioning base code, and the said phase difference evaluation part judges whether it is in the said determined phase difference tolerance range. You may comprise a positioning apparatus.

According to this, since a positioning device has a phase difference tolerance range determination part, it is possible to determine a phase difference tolerance range based on the reception state of a positioning basic code.

And since a positioning device has a phase difference evaluation part, it can judge whether a phase difference exists in a phase difference tolerance range. For this reason, the positioning device can verify the accuracy of the phase.

Moreover, since a positioning device has a positioning part, it can position a present position using the phase corresponding to the phase difference within a phase difference tolerance range.

For this reason, the positioning apparatus can accurately position the positioning device after verifying the accuracy of the phase of the positioning basic code under a weak electric field.

Moreover, in 1 aspect of this invention, the said reception state may comprise the positioning apparatus containing the number of the said transmission sources which the said positioning apparatus has received the said positioning basic code.

According to this, the positioning apparatus can narrow the phase difference allowable range, for example, as the positioning apparatus receives the positioning basic code, so that only a relatively high precision phase can be used for positioning.

For this reason, the positioning device can perform positioning using a relatively high precision phase under a weak electric field having a weak radio wave strength.

Moreover, in 1 aspect of this invention, the said reception state may comprise the positioning apparatus containing the signal strength of the said positioning basic code which the said positioning apparatus is receiving.

According to this, the positioning device can narrow the phase difference allowable range and use only a relatively high precision phase for positioning, for example, as the number of sources having a strong signal strength of the positioning basic code received by the positioning device is narrower.

Thereby, the positioning device can perform positioning using a relatively high phase under a weak electric field with a small propagation intensity.

Moreover, in 1 aspect of this invention, the said reception state may comprise the positioning apparatus containing the information which shows whether the drift of the reference clock of the said positioning apparatus exists in the drift tolerance range prescribed | regulated previously.

According to this, the positioning device can calculate the phase more accurately as the drift is smaller.

For example, when the drift is within the drift allowable range, the phase difference allowable range is narrowed, so that only a phase with relatively high precision can be used for positioning.

For this reason, a positioning device can perform positioning using the said phase with a relatively high degree | precision under the weak electric field with a weak propagation intensity.

Moreover, in 1 aspect of this invention, the said reception state may comprise the positioning device containing the information which shows the elapsed time after starting the said correlation process.

According to this, the longer the elapsed time, the more precisely the phase of the positioning basic code can be specified. For example, the longer the elapsed time is, the narrower the phase difference allowable range can be, and only a relatively precise phase can be used for positioning.

For this reason, a positioning device can perform positioning using the said phase with relatively high precision, under the weak electric field with a weak propagation intensity.

In one aspect of the present invention, the phase difference allowable range determination unit sets the phase difference allowable range narrower as the number of the source sources that the positioning device receives the positioning base code increases, and the positioning device sets the positioning base code. You may comprise the positioning apparatus which sets the said phase difference tolerance range so that the number of the said originating sources which receive | receives is small.

According to this, since a positioning apparatus sets a narrow phase difference tolerance range, so that the positioning apparatus receives the positioning basic code, the positioning apparatus can perform positioning using a high precision phase.

In addition, since the positioning device sets the phase difference allowable range wider as the positioning device receives the positioning base code, the possibility of calculating the positioning position can be increased.

Moreover, the said source may comprise the positioning device which is a satellite positioning system (SPS) satellite.

Another aspect of the present invention is a phase calculation step of performing a correlation process between a predetermined replica positioning base code and a positioning base code from a predetermined source to calculate a phase of the positioning base code, and the above-mentioned used at the time of last positioning. A prediction phase calculation step of calculating a prediction phase when the current phase is predicted based on a phase, a Doppler shift of the frequency of the radio wave carrying the positioning base code, and the elapsed time from the last positioning time, and the phase A phase difference evaluation step of determining whether or not the phase difference between the phase and the predicted phase calculated in the calculating step is within a predetermined phase difference tolerance range, and the current position using the phase corresponding to the phase difference within the phase difference tolerance range It relates to a positioning control method, having a positioning step of positioning.

In one aspect of the present invention, the phase calculating step includes the correlation processing of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, thereby executing the phase of the positioning base code. Wherein the positioning step includes selecting a phase having the minimum phase difference for each of the source sources and selecting the phase among the phases corresponding to the phase difference within the phase difference tolerance range, and selecting the phase; A prescribed number of steps defined by a selection phase first evaluation step of determining whether or not the signal strength of a phase is maximum and the number of times the phase in the frequency series to which the selection phase belongs is continuously within the phase difference tolerance range. Has a selection phase second evaluation step of determining whether or not it is within a range; When the determination result by the phase 1 evaluation step and / or the determination result by the selection phase 2 evaluation step is positive, the positioning control method is a step of positioning the current position using the selection phase. do.

Moreover, in 1 aspect of this invention, it has a phase difference tolerance range determination step of determining the said phase difference tolerance range based on the reception state of the said positioning base code, The said phase difference evaluation step is whether it is in the said determined phase difference tolerance range. You may comprise the positioning control method which is a step of determining the.

Moreover, in one aspect of the present invention, a phase calculation step of performing a correlation process of a predetermined replica positioning base code and a positioning base code from a predetermined source to calculate a current phase of the positioning base code, and the previous positioning Prediction phase calculation which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning time used at the time And a phase difference evaluation step of determining whether a phase difference between the current phase and the predicted phase calculated in the phase calculation step is within a predetermined phase difference tolerance range, and the phase difference corresponding to the phase difference within the phase difference tolerance range. Use phase to relate to a positioning control program for executing a positioning step of positioning a current position. .

In one aspect of the present invention, the phase calculating step includes the correlation processing of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, thereby executing the phase of the positioning base code. Wherein the positioning step includes selecting a phase having the minimum phase difference for each of the source sources and selecting the phase among the phases corresponding to the phase difference within the phase difference tolerance range, and selecting the phase; A prescribed number of steps defined by a selection phase first evaluation step of determining whether or not the signal strength of a phase is maximum and the number of times the phase in the frequency series to which the selection phase belongs is continuously within the phase difference tolerance range. Has a selection phase second evaluation step of determining whether or not it is within a range; When the determination result by the first evaluation step and / or the determination result by the second evaluation step is positive, the positioning control program, which is a step of positioning the current position using the selection phase, may be constructed. do.

Moreover, in 1 aspect of this invention, the said phase difference tolerance range determination step which determines the said phase difference tolerance range is performed to the said computer based on the reception state of the said positioning base code, The said phase difference evaluation step is the said determined phase difference tolerance range You may comprise a positioning control program which is a step of determining whether it is inside.

Moreover, in one aspect of the present invention, a phase calculation step of performing a correlation process of a predetermined replica positioning base code and a positioning base code from a predetermined source to calculate a current phase of the positioning base code, and the previous positioning Prediction phase calculation which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning time used at the time And a phase difference evaluation step of determining whether or not a phase difference between the phase and the predicted phase calculated in the phase calculation step is within a predetermined phase difference tolerance range, and the phase corresponding to the phase difference within the phase difference tolerance range. Using a computer to record the positioning control program for executing the positioning step of positioning the current position. Relates to a readable recording medium.

In one aspect of the present invention, the phase calculating step includes the correlation processing of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, thereby executing the phase of the positioning base code. Wherein the positioning step includes selecting a phase having the minimum phase difference for each of the source sources and selecting the phase among the phases corresponding to the phase difference within the phase difference tolerance range, and selecting the phase; A prescribed number of steps defined by a selection phase first evaluation step of determining whether or not the signal strength of a phase is maximum and the number of times the phase in the frequency series to which the selection phase belongs is continuously within the phase difference tolerance range. Has a selection phase second evaluation step of determining whether or not it is within a range; Recording the positioning control program, which is a step of positioning the current position using the selection phase when the determination result by the phase 1 evaluation step and / or the selection phase by the second evaluation step is positive. You may comprise a recording medium.

Moreover, in 1 aspect of this invention, the said phase difference tolerance range determination step which determines the said phase difference tolerance range is performed to the said computer based on the reception state of the said positioning base code, The said phase difference evaluation step is the said determined phase difference tolerance range You may comprise the recording medium which recorded the said positioning control program which is a step of determining whether it is inside.

1 is a schematic diagram illustrating a terminal and the like of the first embodiment.

2 is a conceptual diagram illustrating a positioning method in the first embodiment.

3 is an explanatory diagram of correlation processing in the first embodiment;

4 is a diagram illustrating an example of a relationship between a correlation integration value and a code phase in the first embodiment.

Fig. 5 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the first embodiment.

Fig. 6 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the first embodiment.

Fig. 7 is a schematic diagram showing a main hardware configuration of a terminal in the first embodiment.

8 is a schematic diagram illustrating an example of a configuration of a GPS device according to the first embodiment.

Fig. 9 is a schematic diagram showing a main software configuration of a terminal in the first embodiment.

FIG. 10 is an explanatory diagram of an estimated frequency calculation program in the first embodiment. FIG.

11A is an explanatory diagram of a measurement calculation program in the first embodiment.

11B is an explanatory diagram of a measurement calculation program in the first embodiment.

11C is an explanatory diagram of a measurement calculation program in the first embodiment.

Fig. 12 is an explanatory diagram of a predictive code phase calculating program according to the first embodiment.

Fig. 13 is a schematic flowchart showing an operation example of a terminal in the first embodiment.

Fig. 14 is a schematic diagram showing a terminal and the like of the second embodiment.

Fig. 15 is a conceptual diagram illustrating a positioning method in the second embodiment.

Fig. 16 is an explanatory diagram of correlation processing in the second embodiment.

Fig. 17 is a diagram showing an example of the relationship between the correlation integration value and the code phase in the second embodiment.

Fig. 18 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the second embodiment.

Fig. 19 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the second embodiment.

Fig. 20 is a schematic diagram showing a main hardware configuration of a terminal in the second embodiment.

21 is a schematic diagram illustrating an example of a configuration of a GPS device according to a second embodiment.

Fig. 22 is a schematic diagram showing a main software configuration of a terminal in the second embodiment.

Fig. 23 is an explanatory diagram of an estimated frequency calculation program in the second embodiment.

24A is an explanatory diagram of a measurement calculation program in the second embodiment.

24B is an explanatory diagram of a measurement calculation program in the second embodiment.

24C is an explanatory diagram of a measurement calculation program in the second embodiment.

Fig. 25 is a diagram showing an example of current measurement information in the second embodiment.

The figure which shows an example of last measurement information in 2nd Embodiment.

Fig. 27 is an explanatory diagram of a predictive code phase calculating program according to the second embodiment.

Fig. 28 is a diagram showing an example of prediction code phase information in the second embodiment.

Fig. 29 is an explanatory diagram of a code phase selection program in the second embodiment.

Fig. 30 is a diagram showing an example of selection code phase information in the second embodiment.

Fig. 31A is an explanatory diagram of a selection code phase second evaluation program in the second embodiment.

Fig. 31B is an explanatory diagram of a selection code phase second evaluation program in the second embodiment.

Fig. 31C is an explanatory diagram of a selection code phase second evaluation program in the second embodiment;

32 is a diagram showing an example of positioning use code phase information according to the second embodiment;

Fig. 33 is a schematic flowchart showing an example of operation of a terminal in the second embodiment.

Fig. 34 is a schematic flowchart showing an example of operation of a terminal in the second embodiment.

Fig. 35 is a schematic diagram showing a terminal and the like of the third embodiment.

36 is a conceptual diagram illustrating a positioning method in a third embodiment.

37 is an explanatory diagram of correlation processing in the third embodiment;

FIG. 38 shows an example of a relationship between a correlation integration value and a code phase in a third embodiment; FIG.

Fig. 39 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the third embodiment.

Fig. 40 is a diagram showing an example of the relationship between a candidate code phase and time lapse in the third embodiment.

Fig. 41 is a schematic diagram showing a main hardware configuration of a terminal in the third embodiment.

42 is a schematic diagram illustrating an example of a configuration of a GPS device according to a third embodiment.

Fig. 43 is a schematic diagram showing a main software configuration of a terminal in the third embodiment.

Fig. 44 is an explanatory diagram of an estimated frequency calculation program in the third embodiment.

45A is an explanatory diagram of a measurement calculation program in the third embodiment.

45B is an explanatory diagram of a measurement calculation program in the third embodiment;

45C is an explanatory diagram of a measurement calculation program in the third embodiment;

Fig. 46 is an explanatory diagram of a predictive code phase calculating program according to the third embodiment.

Fig. 47 is an explanatory diagram of a code phase threshold value setting program according to the third embodiment.

48 is a schematic flowchart illustrating an operation example of a terminal in the third embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described in detail, referring an accompanying drawing.

In addition, since embodiment described below is a suitable specific example of this invention, although various technically preferable limitation is added, the scope of the present invention limits the present invention especially in the following description. Unless otherwise described, it is not limited to these forms.

In addition, three embodiment is largely described below. Each embodiment includes the thing which is common. However, in order to clarify that the terminal of each embodiment can be configured independently, common matters are overlapped repeatedly.

[First embodiment]

1 is a schematic diagram illustrating a terminal 1020 and the like of the first embodiment.

As shown in FIG. 1, the terminal 1020 is a positioning satellite, for example, from radio wave S1, from a GPS (Global Positioning System) satellites 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h. S2, S3, S4, S5, S6, S7 and S8) can be received. The GPS satellites 12a and the like are also examples of sources. In addition, the source may be a satellite positioning system (SPS) satellite and is not limited to the GPS satellite.

Various codes (signs) are carried in the radio wave S1 and the like. One of them is the C / A code (Sca). This C / A code Sca is a signal having a bit rate of 1.023 Mbps and a bit length of 1,023 bits (= 1 msec). The C / A code Sca is composed of 1,023 chips. The terminal 1020 is an example of a positioning apparatus for positioning the current position, and performs positioning of the current position using this C / A code. This C / A code Sca is an example of positioning basic code.

In addition, information on the radio wave S1 and the like includes Almanac (Sal) and Epimeris (Seh). Almanac (Sal) is information indicating the rough satellite trajectory of all GPS satellites 12a and the like, and Epimeris (Seh) is information indicating the precise satellite trajectory of each GPS satellite 12a and the like. Almanak (Sal) and Epimeris (Seh) are collectively called navigation messages.

The terminal 1020 can specify the phase of the C / A code from three or more different GPS satellites 12a or the like, for example, to determine the current position.

2 is a conceptual diagram illustrating an example of the positioning method.

As shown in FIG. 2, for example, it can be conceived that C / A codes are continuously arranged between the GPS satellite 12a and the terminal 1020. In addition, since the distance between the GPS satellite 12a and the terminal 1020 cannot be limited to an integer multiple of the length (300 km (km)) of the C / A code, the code singular part (C / Aa) exist. That is, between the GPS satellite 12a and the terminal 1020, there is an integer multiple of the C / A code and a singular portion. The length of the sum of the integral part and the singular part of the C / A code is a pseudo distance. The terminal 1020 performs positioning using a pseudo distance with respect to three or more GPS satellites 12a and the like.

In this embodiment, the singular part C / Aa of a C / A code is called a code phase. For example, the code phase may be represented by the number of 1,023 chips of the C / A code, or may be expressed in terms of distance. When calculating the pseudo distance, the code phase is converted into a distance.

The position on the orbit of the GPS satellite 12a can be calculated using Epimeris (Seh). For example, if the distance between the position on the orbit of the GPS satellite 12a and the initial position QA0 to be described later is calculated, the integer multiple of the C / A code can be specified. In addition, since the length of the C / A code is 300 kilometers (km), the position error of the initial position QA0 needs to be within 150 kilometers (km).

As shown in Fig. 2, correlation processing is performed while shifting the phase of the replica C / A code in the arrow X1 direction, for example. At this time, the terminal 1020 performs correlation processing while varying the synchronization frequency. This correlation process consists of a coherent process and an incoherent process mentioned later.

The phase where the correlation integration value is maximum is the code number (C / Aa).

In addition, unlike the first embodiment, the terminal 1020 may perform positioning using, for example, radio waves from the communication base station of the cellular phone. In addition, unlike the first embodiment, the terminal 1020 may receive radio waves from a LAN (Local Area Network) to perform positioning.

3 is an explanatory diagram of correlation processing.

Coherent is a process of correlating a C / A code received by the terminal 1020 with a replica C / A code. The replica C / A code is a code generated by the terminal 1020. The replica C / A code is an example of a replica positioning basic code.

For example, as shown in FIG. 3, if the coherent time is 10 msec, the correlation value of the C / A code and replica C / A code synchronously accumulated in 10 msec time is calculated. As a result of the coherent process, the correlated phase (code phase) and the correlation value are output.

Incoherent is a process of calculating a correlation integration value (incoherent value) by integrating a correlation value of a coherent result.

As a result of the correlation process, the code phase output by the coherent process and the correlation integration value are output.

4 is a diagram illustrating an example of a relationship between a correlation integration value and a code phase.

The code phase CP1 corresponding to the maximum value Pmax of the correlation integration value in FIG. 4 is the code phase of the replica C / A code, that is, the code phase of the C / A code.

For example, the terminal 1020 sets the correlation integration value of the one with the smaller correlation integration value as the correlation integration value Pnoise among the code phases that are half of the chip phase from the code phase CP1. .

The terminal 1020 defines a value obtained by dividing the difference between Pmax and Pnoise by Pmax as the signal strength (XPR). Signal strength XPR is an example of signal strength.

And when the XPR is 0.2 or more, for example, when the XPR is 0.2 or more, the terminal 1020 makes a code phase candidate which uses code phase CP1 for positioning. Hereinafter, this code phase is called "candidate code phase." The candidate code phase is a candidate used for positioning, and the terminal 1020 is not limited to actually used for positioning.

5 and 6 are diagrams showing an example of the relationship between the candidate code phase and time lapse.

5 shows a state where the GPS satellite 12a is nearing the terminal 1020, for example.

When the GPS satellite 12a approaches the terminal 1020, the distance between the GPS satellite 12a and the terminal 1020 becomes short, so that the candidate code phase C1 approaches 0 with time.

The synchronization frequency F1 is set to increase with time. This is because the Doppler shift caused by the GPS satellite 12a nearing the terminal 1020 increases the arrival frequency when the radio wave S1 reaches the terminal 1020.

The terminal 1020 uses three frequency sequences F1, F2, and F3, for example, as shown in FIG. The frequency series F1 and the like are examples of frequency series. The frequency series F1 and F2 are separated by a frequency width of 50 hertz (Hz). The frequency series F1 and F3 are separated by a frequency width of 50 hertz (Hz). A frequency interval of 50 hertz (Hz) is predefined. In other words, the frequency interval of 50 hertz (Hz) is an example of the frequency interval. This frequency interval is prescribed in less than the step interval of the frequency search in the correlation process performed by the terminal 1020. For example, if the step interval of the frequency search is 100 hertz (Hz) (see Fig. 11B), it is prescribed in less than 100 hertz (Hz).

The frequency sequence F1 or the like may be a plurality, and, unlike the first embodiment, for example, four or more may be used.

As shown in FIG. 6, each frequency series F1 etc. is set so that it may change with time over anticipation of the Doppler shift of arrival frequency.

And any one of each frequency series F1 etc. will follow the Doppler shift of arrival frequency most accurately.

The code phase C1 is calculated in the frequency series F1. Then, the code phase C2 is calculated in the frequency sequence F2. Then, the code phase C3 is calculated in the frequency sequence F3.

As described above, the three code phases C1 and the like are calculated in parallel, but it can be assumed that the candidate code phases calculated with the highest signal strength XPR have the highest reliability.

By the way, it cannot be limited that XPR maintains the highest frequency series F1 and the like. For example, as shown in FIG. 6, for example, between time t1 and t2, XPR of the candidate code phase C1 calculated with the frequency series F1 is the highest, and between time t2 and t3. In this case, the XPR of the candidate code phase C2 calculated by the frequency series F2 is the highest.

Based on the expected Doppler shift, the frequency of each frequency series F1 or the like is changed, so that the candidate code phase calculated by one frequency series is more accurate than the candidate code phase calculated by another frequency series. Will be higher. In other words, for example, the frequency sequence F1 will continue to follow the actual reached frequency most accurately than the other frequency sequences F2 and F3.

For this reason, when the frequency sequence is changed over time, the candidate code phase calculated in the state of high XPR is not limited to the highest accuracy.

In this regard, the terminal 1020 can be accurately positioned after verifying the precision of the candidate code phase under the weak electric field by the following hardware configuration and software configuration.

(About main hardware configuration of terminal 1020)

7 is a schematic diagram illustrating a main hardware configuration of the terminal 1020.

As shown in FIG. 7, the terminal 1020 has a computer, and the computer has a bus 1022. A CPU (Central Processing Unit) 1024, a storage device 1026, and the like are connected to the bus 1022. The memory device 1026 is, for example, a random access memory (RAM), a read only memory (ROM), or the like.

In addition, an input device 1028, a power supply device 1030, a GPS device 1032, a display device 1034, a communication device 1036, and a clock 1038 are connected to the bus 1022.

(About the structure of GPS device 1032)

8 is a schematic diagram showing the configuration of the GPS device 1032.

As shown in FIG. 8, the GPS apparatus 1032 is comprised from the RF part 1032a and the base band part 1032b.

The RF unit 1032a receives the radio wave S1 and the like through the antenna 1033a. The LNA 1033b, which is an amplifier, amplifies a signal such as a C / A code carried in the radio wave S1. The mixer 1033c then down converts the frequency of the signal. An orthogonal (IQ) detector 1033d then IQ separates the signal. Subsequently, the A / D converters 1033e1 and 1033e2 are configured to convert the IQ separated signals into digital signals, respectively.

The base band section 1032b is configured to receive a signal converted into a digital signal from the RF section 1032a, sample and integrate the signal, and take correlation with the C / A code held by the base band 1032b. It is. The base band part 1032b has 128 correlators (not shown) and an accumulator (not shown), for example, and can perform a correlation process in 128 phases simultaneously. The correlator is a configuration for performing the coherent process described above. The accumulator is a configuration for performing the incoherent process described above.

(About main software configuration of terminal 1020)

9 is a schematic diagram showing the main software configuration of the terminal 1020.

As shown in FIG. 9, the terminal 1020 includes a control unit 1100 for controlling each unit, a GPS unit 1102 corresponding to the GPS device 1032 of FIG. 7, and a time unit 1104 corresponding to the clock 1038. Has a back.

The terminal 1020 also has a first storage unit 1110 for storing various programs and a second storage unit 1150 for storing various information.

As shown in FIG. 9, the terminal 1020 stores the navigation message 1152 in the second storage unit 1150. Navigation message 1152 includes almanac 1152a and epimeris 1152b.

The terminal 1020 uses almanac 1152a and epimeris 1152b for positioning.

As shown in FIG. 9, the terminal 1020 stores the initial positional information 1154 in the second storage unit 1150. The initial position QA0 is the last positioning position, for example.

As shown in FIG. 9, the terminal 1020 stores the observable satellite calculation program 1112 in the first storage unit 1110. The observable satellite calculation program 1112 is a program for the control unit 1100 to calculate the observable GPS satellite 12a and the like on the basis of the initial position QA0 indicated in the initial position information 1154.

Specifically, the control unit 1100 determines the GPS satellite 12a or the like that can be observed at the current time measured by the timekeeping unit 1104 with reference to the almanac 1152a. The control unit 1100 stores the observable satellite information 1156 indicating the observable GPS satellite 12a and the like (hereinafter, referred to as "observable satellite") in the second storage unit 1150. In the first embodiment, the observable satellites are GPS satellites 12a to 12h (see FIGS. 1 and 9).

As shown in FIG. 9, the terminal 1020 stores the estimated frequency calculating program 1114 in the first storage unit 1110. The estimated frequency calculation program 1114 is a program for the control unit 1100 to estimate a reception frequency such as the radio wave S1 from the GPS satellite 12a or the like.

This reception frequency is the arrival frequency when the radio wave S1 reaches the terminal 1020. More specifically, this reception frequency is an intermediate frequency (IF) when the radio wave S1 reaches the terminal 1020 and is down-converted in the terminal 1020.

10 is an explanatory diagram of the estimated frequency calculating program 1114.

As shown in FIG. 10, the control unit 1100 adds the Doppler shift H2 to the transmission frequency H1 from the GPS satellite 12a or the like and calculates the estimated frequency A1. The outgoing frequency H1 from the GPS satellites 12a and the like is conventional, for example, 1,575.42 MHz.

The Doppler shift H2 is generated by the relative movement of each GPS satellite 12a and the like and the terminal 1020. The control unit 1100 calculates the line speed (speed relative to the direction of the terminal 1020) of each GPS satellite 12a at the present time based on the epimeris 1152b and the initial position QA0. Then, the Doppler shift H2 is calculated based on the line speed.

The control unit 1100 calculates the estimated frequency A1 for each GPS satellite 12a or the like that is an observable satellite.

In addition, the estimated frequency A1 includes an error equal to the drift of the clock (reference oscillator: not shown) of the terminal 1020. Drift is a change in oscillation frequency due to temperature change.

For this reason, the control part 1100 searches the radio wave S1 etc. at the frequency of predetermined width centering on the estimated frequency A1. For example, the radio wave S1 or the like is searched for at a frequency of 100 Hz in a range of a frequency from (A1-100) kHz to (A1 + 100) kHz.

As shown in FIG. 9, the terminal 1020 stores the measurement calculation program 1116 in the first storage unit 1110. In the measurement calculation program 1116, the control unit 1100 performs a correlation process between the C / A code received from the GPS satellite 12a and the like and the replica C / A code generated by the terminal 1020, and the correlation integration value. Is a program for calculating a measurement including a maximum value Pmax, a correlation integration value Pnoise of noise, a candidate code phase, and a reception frequency. The measurement calculation program 1116 and the control unit 1100 are examples of the phase calculation unit, and are examples of the reception frequency specifying unit.

11A to 11C are explanatory diagrams of the measurement calculation program 1116.

As shown in FIG. 11A, the control unit 1100 divides one chip of the C / A code into equal intervals, for example, by the base band unit 1032b to perform a correlation process. One chip of the C / A code is divided into 32, for example. That is, correlation processing is performed at intervals of the phase width (first phase width W1) of one third of the chip. The phase of the interval of the first phase width W1 when the control unit 1100 performs correlation processing is referred to as a first sampling phase SC1.

The first phase width W1 is defined as the phase width at which the correlation maximum value Pmax can be detected when the signal strength when the radio wave S1 or the like reaches the terminal 1020 is -155 dBm or more. . Simulation results show that the correlation width Pmax can be detected even with a weak electric field if the signal width is -155 dBm or more with a phase width of 1/32 chips.

As shown in FIG. 11B, the control unit 1100 performs correlation processing while shifting the frequency range of ± 100 kHz by the first phase width W1 around the estimated frequency A1. At this time, correlation processing is performed while shifting the frequency by 100 Hz.

As shown in FIG. 11C, the correlation value integration P corresponding to the phases C1 to C64 for two chips is output from the base band portion 1032b. Each phase C1 to C64 is the first sampling phase SC1.

The control unit 1100 searches, for example, from the first chip to the first chip of the C / A code based on the measurement calculation program 1116.

The control unit 1100 calculates the XPR based on Pmax and Pnoise, and sets the code phase CPA1 and the reception frequencies fA1, PAmax1, and PAnoise1 corresponding to the state with the largest XPR as the current measurement information 1160. . The code phase CPA1 and the reception frequencies fA1, PAmax1 and PAnoise1 are collectively called a measurement. The terminal 1020 calculates a measure for each GPS satellite 12a or the like.

In addition, the code phase CPA1 is converted into distance. As described above, the code length of the C / A code is, for example, 300 kilometers (km), so that the code phase, which is the singular part of the C / A code, can also be converted into distance.

The control unit 1100 calculates a measure with respect to six GPS satellites 12a etc. among the observable satellites, for example. In addition, the measurement about the same GPS satellite 12a etc. is called the corresponding measurement. For example, the code phase CPA1 for GPS satellite 12a and the frequency fA1 for GPS satellite 12a are corresponding measurements. The frequency fA1 is a reception frequency when the radio wave S1 from the GPS satellite 12a is received.

In addition, unlike the first embodiment, as a method of correlation processing, a narrow correlator (see, for example, Japanese Patent Laid-Open No. 2000-312163) may be employed.

As shown in FIG. 9, the terminal 1020 stores the measurement storage program 1118 in the first storage unit 1110. The measurement storage program 1118 is a program for the control unit 1100 to save the measurement in the second storage unit 1150.

The control unit 1100 stores the new measurement as the current measurement information 1160 in the second storage unit 1150, and stores the existing current measurement information 1160 as the previous measurement information 1162. It is stored in the storage unit 1150. The previous measurement information 1162 includes the code phase CPA0 and the frequencies fA0, PAmax0 and PAnoise0 at the time of the last positioning.

As shown in FIG. 9, the terminal 1020 stores the frequency evaluation program 1120 in the first storage unit 1110. The frequency evaluation program 1120 allows the controller 1100 to determine whether a frequency difference between the reception frequency fA0 at the last positioning and the reception frequency fA1 at the current positioning is within the frequency threshold α1. Program. The range within the frequency threshold α1 is previously defined by a threshold value less than the frequency interval of the frequency series F1, F2, and F3. As described above, if the frequency interval is 50 hertz (Hz), the frequency threshold α1 is, for example, 30 hertz (Hz). The frequency evaluation program 1120 and the control unit 1100 described above are examples of the frequency difference evaluation unit. The range within the frequency threshold α1 is an example within the frequency difference allowable range predefined.

As shown in FIG. 9, the terminal 1020 stores the predictive code phase calculating program 1122 in the first storage unit 1110. The predictive code phase calculation program 1122 is controlled by the control unit 1100 based on the code phase CPA0 at the last positioning, the Doppler shift such as the radio wave S1, and the elapsed time dt from the previous positioning. The program predicts the current phase and calculates the predictive code phase (CPAe). Prediction code phase (CPAe) is an example of the prediction phase. The predictive code phase calculating program 1122 and the control unit 1100 are examples of the predictive phase calculating unit.

The predictive code phase CPAe is converted into distances.

12 is an explanatory diagram of a predictive code phase calculating program 1122.

As shown in FIG. 12, the control unit 1100 calculates the prediction code phase CPAe according to, for example, Equation 1.

As shown in Formula 1, the control part 1100 has elapsed time from the time of last positioning from the code phase CPA0 at the time of last positioning to the relative movement speed of the GPS satellite 12a and the terminal 1020, for example. The prediction code phase CPAe is calculated by subtracting the value multiplied by (dt).

In addition, in Formula 1, prediction code phase CPAe and last code phase CPA0 are converted into distance.

Here, the radio wave S1 and the like propagate at the light beam. For this reason, by dividing the luminous flux by the transmission frequency H1 such as the radio wave S1, it is possible to calculate the approximate speed corresponding to one hertz (Hz) of the Doppler shift. In other words, a Doppler shift of plus (+) 1 hertz (Hz) means that the GPS satellite 12a is approaching the terminal 1020 at 0.19 meters per second (m / s). For this reason, the prediction code phase CPAe becomes shorter than the code phase CPA0 at the time of last positioning. Here, the Doppler shift is, for example, the difference between the frequency fA0 at the time of last positioning and the outgoing frequency H1.

On the other hand, the Doppler shift is negative one-hertz (Hz) that the GPS satellite 12a is moving away from the terminal 1020 at 0.19 meters per second (m / s). For this reason, the prediction code phase CPAe becomes longer than the code phase CPA0 at the time of last positioning.

In addition, Formula 1 is established on the condition that elapsed time from last positioning time is a short time. In other words, Equation 1 holds as long as the relationship between the code phase and the elapsed time can be represented as a straight line on the graph.

Unlike the first embodiment, the average value of the difference between the frequency fA0 at the previous positioning and the outgoing frequency H1 and the difference between the frequency fA1 at the current positioning and the outgoing frequency H1 is measured. It may be a side. This makes it possible to calculate the prediction code phase CPAe more accurately.

The control unit 1100 stores the predictive code phase information 1164 indicating the calculated predictive code phase CPAe in the second storage unit 1150.

As shown in FIG. 9, the terminal 1020 stores the code phase evaluation program 1124 in the first storage unit 1110. In the code phase evaluation program 1124, the control unit 1100 determines that the code phase difference between the current code phase CPA1 and the predictive code phase CPAe is a code phase threshold β1 (hereinafter referred to as “threshold value β1”). It is a program for judging whether or not it is. The range below the threshold value β1 is an example within the phase difference tolerance range. The code phase evaluation program 1124 and the control unit 1100 are examples of the phase difference evaluation unit.

The threshold value β1 is predefined. The threshold value β1 is 80 meters (m), for example.

The control unit 1100 uses the code phase CPA1 determined by the above-described frequency evaluation program 1120 as the frequency difference equal to or less than the threshold α1 to be the object of determination based on the code phase evaluation program 1124.

As shown in FIG. 9, the terminal 1020 stores the positioning use code phase determination program 1126 in the first storage unit 1110. The positioning use code phase determination program 1126 includes a code phase such as the GPS satellite 12a in which the control unit 1100 is a frequency difference within the frequency threshold α1 and a code phase difference less than or equal to the threshold β1. It is a program for determining (CPA1) and the like as the positioning use code phase (CPA1f).

The code phase CPA1 such as the GPS satellite 12a or the like corresponding to the frequency difference that is not within the frequency threshold α1 is excluded from the positioning without being determined as the positioning use code phase CPA1f. The code phase CPA1 corresponding to the frequency difference within the frequency threshold α1 and corresponding to the code phase difference below the threshold β1 is used for positioning. That is, the positioning use code phase determination program 1126 and the control unit 1100 are examples of the phase exclusion unit.

In the first embodiment, the positioning use code phase CPA1f is, for example, CPA1fa, CPA1fb, CPA1fc, and CPA1fd corresponding to the GPS satellites 12a, 12b, 12c, and 12d, respectively.

The control unit 1100 stores the positioning use code phase information 1166 indicating the positioning use code phase CPA1f in the second storage unit 1150.

As shown in FIG. 9, the terminal 1020 stores the positioning program 1128 in the first storage unit 1110. The positioning program 1128 is a program for the control unit 1100 to position the current position using the positioning use code phase CPA1f. The positioning program 1128 and the control unit 1100 are examples of the positioning unit.

The positioning use code phase CPA1f is a code phase CPA1 within the above-described threshold value β1 and the like. In other words, positioning the current position using the positioning use code phase CPA1f is equivalent to positioning the current position using the code phase CPA1 within the threshold β1 or the like.

When there are three or more positioning use code phases CPA1f, the control part 1100 performs positioning of the present position using those positioning use code phases CPA1f, and calculates positioning position QA1.

The control unit 1100 stores the positioning position information 1168 indicating the calculated positioning position QA1 in the second storage unit 1150.

As shown in FIG. 9, the terminal 1020 stores the positioning position output program 1130 in the first storage unit 1110. The positioning position output program 1130 is a program for the control unit 1100 to display the positioning position QA1 on the display device 1034 (see FIG. 7).

The terminal 1020 is configured as described above.

The terminal 1020 may determine whether the code phase difference between the current code phase CPA1 and the predictive code phase CPAe is equal to or less than a predetermined threshold value β1. For this reason, the terminal 1020 can verify the precision of the code phase CPA1.

In addition, the terminal 1020 can position the current position by using the code phase CPA1 corresponding to the code phase difference equal to or less than the threshold value β1.

For this reason, the terminal 1020 can perform the positioning with high accuracy after verifying the precision of the code phase of the positioning basic code under a weak electric field having a weak signal strength.

In addition, the terminal 1020 can exclude the code phase CPA1 corresponding to the frequency fA1 outside the range within the frequency threshold α1 from positioning.

This means that the terminal 1020 can not only verify the accuracy of the code phase CPA1 of the C / A code, but also verify the accuracy of the reception frequency fA1 when the code phase CPA1 has been calculated. it means.

For this reason, after verifying the precision of the code phase of positioning base code, the terminal 1020 can carry out positioning with more precision under the weak electric field with a weak signal strength.

As mentioned above, although the structure of the terminal 1020 which concerns on 1st Embodiment is demonstrated, the operation example is demonstrated mainly using FIG.

13 is a schematic flowchart showing an operation example of the terminal 1020.

First, the terminal 1020 receives the radio wave S1 and the like and calculates the measurement (step S101 in FIG. 13). This step S101 is an example of a phase calculation step.

Subsequently, the terminal 1020 stores the measurement (step S102).

Subsequently, the terminal 1020 determines whether or not the absolute value of the frequency difference between the present frequency fA1 and the previous frequency fA0 is equal to or less than the frequency threshold α1 (step S103).

In step S103, the terminal 1020 does not use the code phase CPA1 corresponding to the frequency difference determined not to be below the frequency threshold α1 for positioning (step S109). In other words, the positioning use code phase CPA1f is not used.

In contrast, in step S103, for the code phase CPA1 corresponding to the frequency difference determined as equal to or less than the frequency threshold α1, the corresponding prediction code phase CPAe is calculated (step S104). This step S104 is an example of the predictive phase calculation step.

Subsequently, the terminal 1020 determines whether the absolute value of the code phase difference between the code phase CPA1 and the predictive code phase CPAe is equal to or less than the threshold β1 (step S105). This step S105 is an example of a phase evaluation step. The terminal 1020 sets the code phase CPA1 in which the absolute value of the code phase difference is equal to or less than the threshold value β1 as the positioning use code phase CPA1f.

Subsequently, the terminal 1020 determines whether there are three or more positioning use code phases CPA1f (step S106).

In step S106, when the terminal 1020 determines that the positioning use code phase CPA1f is less than three, since positioning is impossible, it ends without positioning.

In contrast, in step S106, when the terminal 1020 determines that there are three or more positioning use code phases CPA1f, the terminal 1020 performs positioning using the positioning use code phases CPA1f (step S107). This step S107 is an example of the positioning step.

Subsequently, the terminal 1020 outputs the positioning position QA1 (see FIG. 9) (step S108).

According to the above steps, the terminal 1020 can perform the positioning with high accuracy after verifying the precision of the phase of the positioning basic code under a weak electric field having a weak signal strength.

[Second embodiment]

14 is a schematic diagram illustrating the terminal 2020 and the like of the second embodiment.

As shown in FIG. 14, the terminal 2020 is radio wave S1, S2, S3, S4 from GPS satellites 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h which are positioning satellites, for example. , S5, S6, S7 and S8) can be received. The GPS satellites 12a and the like are also examples of sources. The positioning satellite is not limited to a GPS satellite, but may be a satellite widely used in a satellite positioing system (SPS).

Various codes (signs) are carried in the radio wave S1 and the like. One of them is the C / A code Sca. This C / A code Sca is a signal having a bit rate of 1.023 Mbps and a bit length of 1,023 bits (= 1 msec). The C / A code Sca is composed of 1,023 chips. The terminal 2020 is an example of a positioning apparatus for positioning the current position, and performs positioning of the current position using this C / A code. This C / A code Sca is an example of positioning basic code.

In addition, information on the radio wave S1 and the like includes almanac (Sal) and epimeris (Seh). Almanac (Sal) is information indicating the rough satellite trajectory of all GPS satellites 12a and the like, and Epimeris (Seh) is information indicating the precise satellite trajectory of each GPS satellite 12a and the like. Almanak (Sal) and Epimeris (Seh) are collectively called navigation messages.

For example, the terminal 2020 can specify the code phase (phase) of the C / A code from three or more different GPS satellites 12a or the like to position the current position.

15 is a conceptual diagram illustrating an example of the positioning method.

As shown in FIG. 15, for example, it can be conceivable that C / A codes are continuously arranged between the GPS satellites 12a and the terminal 2020. In addition, since the distance between the GPS satellite 12a and the terminal 2020 cannot be limited to an integer multiple of the length (300 kilometers (km)) of the C / A code, a code singular part (C / Aa) exists. do. That is, between the GPS satellite 12a and the terminal 2020, there is an integer multiple of the C / A code and a singular portion. The length of the sum of the integral part and the singular part of the C / A code is a pseudo distance. The terminal 2020 performs positioning using a pseudo distance with respect to three or more GPS satellites 12a and the like.

In this embodiment, the singular part C / Aa of a C / A code is called code phase (phase). For example, the code phase may be represented by the number of 1,023 chips of the C / A code, or may be expressed in terms of distance. When calculating the pseudo distance, the code phase is converted into a distance.

The position on the orbit of the GPS satellite 12a can be calculated using Epimeris (Seh). For example, if the distance between the position on the orbit of the GPS satellite 12a and the initial position QB0 to be described later is calculated, the integer multiple of the C / A code can be specified. In addition, since the length of the C / A code is 300 km (km), the position error of the initial position QB0 needs to be within 150 km (km).

And as shown in FIG. 15, a correlation process is performed, moving the phase of a replica C / A code to arrow X1 direction, for example. At this time, the terminal 2020 performs correlation processing while varying the synchronization frequency. This correlation process consists of a coherent process and an incoherent process mentioned later.

The phase where the correlation integration value is maximum is the code number (C / Aa).

In addition, unlike the second embodiment, the terminal 2020 may perform positioning using, for example, radio waves from the communication base station of the cellular phone. In addition, unlike the second embodiment, the terminal 2020 may receive radio waves from a local area network (LAN) to perform positioning.

16 is an explanatory diagram of correlation processing.

Coherent is a process of correlating the C / A code received by the terminal 2020 with a replica C / A code. The replica C / A code is a code generated by the terminal 2020. The replica C / A code is an example of a replica positioning basic code.

For example, as shown in Fig. 16, if the coherent time is 10 msec, the correlation value of the C / A code and replica C / A code synchronously accumulated in a time of 10 msec is calculated. As a result of the coherent processing, the code phase and the correlation value at the time of correlation are output.

Incoherent is a process of calculating a correlation integration value (incoherent value) by integrating a correlation value of a coherent result.

As a result of the correlation process, the code phase output by the coherent process and the correlation integration value are output.

17 is a diagram illustrating an example of a relationship between a correlation integration value and a code phase.

The code phase CP1 corresponding to the maximum value Pmax of the correlation integration value in Fig. 17 is the code phase of the C / A code (the same as the code phase of the replica C / A code).

For example, the terminal 2020 sets the correlation integration value of the one with the smaller correlation integration value as the correlation integration value Pnoise among the code phases that are one-half chip away from the code phase CP1.

The terminal 2020 defines a value obtained by dividing the difference between Pmax and Pnoise by Pmax as signal strength (XPR). Signal strength XPR is an example of signal strength.

And if the XPR is 0.2 or more, for example, when the XPR is 0.2 or more, the terminal 2020 makes it the candidate of the code phase which uses code phase CP1 for positioning. Hereinafter, this code phase is called "candidate code phase." The candidate code phase is a candidate used for positioning, and can not be limited to the fact that the terminal 2020 is actually used for positioning.

18 and 19 are diagrams showing an example of the relationship between the candidate code phase and time lapse.

18 shows a state where the GPS satellite 12a is nearing the terminal 2020, for example.

For example, when the GPS satellite 12a is closer to the terminal 2020, the distance between the GPS satellite 12a and the terminal 2020 is shorter, so that the candidate code phase C1 is close to zero with time. Lose.

The frequency belonging to the frequency sequence F1 is set to increase with time. This is because the Doppler shift caused by the GPS satellite 12a nearing the terminal 2020 increases the arrival frequency when the radio wave S1 reaches the terminal 2020.

The terminal 2020 uses three frequency sequences F1, F2, and F3, for example, as shown in FIG. 19, in order to efficiently synchronize with a varying arrival frequency. The frequency series F1 and the like are examples of frequency series. The frequency sequences F1 and F2 are separated by, for example, a frequency width of 50 hertz (Hz). The frequency series F1 and F3 are also separated by a frequency width of 50 hertz (Hz). A frequency interval of 50 hertz (Hz) is predefined. In other words, the frequency interval of 50 hertz (Hz) is an example of the frequency interval. This frequency interval is prescribed in less than the step interval of the frequency search in the correlation process performed by the terminal 2020. For example, if the step interval of the frequency search is 100 hertz (Hz) (see Fig. 24B), it is prescribed in less than 100 hertz (Hz).

The frequency sequence F1 or the like may be at least one, and unlike the second embodiment, for example, one may be used, or four or more may be provided.

As shown in FIG. 19, each frequency series F1 etc. is set so that it may change with time over anticipation of the Doppler shift of arrival frequency.

And any one of each frequency series F1 etc. will follow the Doppler shift of arrival frequency most accurately.

The code phase C1 is calculated in the frequency series F1. Then, the code phase C2 is calculated in the frequency sequence F2. In the frequency sequence F3, the code phase C3 is calculated.

Thus, although three code phases C1 etc. are calculated in parallel, it is common that the code phase calculated in the state with the highest signal strength XPR is the most reliable.

By the way, it cannot be limited that XPR maintains the highest frequency series F1 and the like. For example, as shown in FIG. 19, for example, between time t1 and t2, XPR of the code phase C1 calculated by the frequency series F1 is the highest, and between time t2 and t3. The XPR of the code phase C2 calculated by the frequency series F2 is the highest.

Since the frequencies of each frequency series F1 and the like are changed based on a common element of the expected Doppler shift, if the code phase calculated by one frequency series is high in accuracy, the other frequency series is continuously used. The precision will be higher than the code phase calculated by.

Here, "high precision" means that the difference between the calculated code phase and the actual code phase is small.

For example, when the accuracy of the frequency series F1 is higher than that of the other frequency series F2 and F3, the frequency series F1 is the most at the actual arrival frequency compared to the other frequency series F2 and F3. Precision will keep on following. For this reason, even when there is a time zone in which the signal strength XPR is lower than the other frequency sequences F2 and F3 in the frequency sequence F1, the candidate code phase calculated in the frequency sequence F1 has the highest precision. will be.

In this regard, the terminal 2020 can perform positioning with high accuracy after verifying the precision of the candidate code phase under a weak electric field in accordance with the following hardware configuration and software configuration.

(About main hardware configuration of terminal 2020)

20 is a schematic diagram illustrating a main hardware configuration of the terminal 2020.

As shown in FIG. 20, the terminal 2020 has a computer, and the computer has a bus 2022. A central processing unit (CPU) 2024, a memory device 2026, and the like are connected to the bus 2022. The storage device 2026 is, for example, a random access memory (RAM), a read only memory (ROM), or the like.

In addition, an input device 2028, a power supply device 2030, a GPS device 2032, a display device 2034, a communication device 2036, and a clock 2038 are connected to the bus 2022.

(About the configuration of the GPS device 2032)

21 is a schematic diagram showing the configuration of the GPS device 2032.

As shown in FIG. 21, the GPS apparatus 2032 is comprised from the RF part 2032a and the base band part 2032b.

The RF unit 2032a receives the radio wave S1 and the like through the antenna 2033a. The LNA 2033b, which is an amplifier, amplifies a signal such as a C / A code carried in the radio wave S1. The mixer 2033c then downconverts the frequency of the signal. The quadrature (IQ) detector 2033d separates the signal from the IQ. Subsequently, the A / D converters 2033e1 and 2033e2 are configured to convert the IQ separated signals into digital signals, respectively.

The base band unit 2032b is configured to receive a signal converted into a digital signal from the RF unit 2032a, sample and integrate the signal, and take correlation with the C / A code held by the base band unit 2032b. It is. The base band unit 2032b includes, for example, 128 correlators (not shown) and accumulators (not shown), and is capable of performing correlation processing in 128 phases at the same time. The correlator is a configuration for performing the coherent process described above. The accumulator is a configuration for performing the incoherent process described above.

(About main software configuration of terminal 2020)

22 is a schematic diagram showing the main software configuration of the terminal 2020.

As shown in FIG. 22, the terminal 2020 is a control part 2100 which controls each part, the GPS 2102 corresponding to the GPS device 2032 of FIG. 20, the clock part 2104 corresponding to the clock 2038, etc. Have

The terminal 2020 further includes a first storage unit 2110 for storing various programs and a second storage unit 2150 for storing various kinds of information.

As shown in FIG. 22, the terminal 2020 stores the navigation message 2152 in the second storage unit 2150. Navigation message 2152 includes almanac (2152a) and epimeris (2152b).

The terminal 2020 uses almanac (2152a) and epimeris (2152b) for positioning.

As shown in FIG. 22, the terminal 2020 stores the initial positional information 2154 in the second storage unit 2150. The initial position QB0 is the last positioning position, for example.

As shown in FIG. 22, the terminal 2020 stores the observable satellite calculation program 2112 in the first storage unit 2110. The observable satellite calculation program 2112 is a program for the control unit 2100 to calculate the observable GPS satellite 12a and the like on the basis of the initial position QB0 indicated in the initial position information 2154.

Specifically, the control unit 2100 determines the GPS satellite 12a or the like that can be observed at the current time measured by the timekeeping unit 2104 with reference to the almanac 2152a. The control unit 2100 stores the observable satellite information 2156 indicating the observable GPS satellite 12a and the like (hereinafter referred to as "observable satellite") in the second storage unit 2150. In 2nd Embodiment, observable satellites are GPS satellites 12a-12h (refer FIG. 1 and FIG. 22).

As shown in FIG. 22, the terminal 2020 stores the estimated frequency satellite calculation program 2114 in the first storage unit 2110. The estimated frequency satellite calculation program 2114 is a program for the control unit 2100 to estimate the received reception frequency of the radio wave S1 or the like from the GPS satellite 12a or the like.

This arrival frequency is a frequency at which the radio wave S1 reaches the terminal 2020. More specifically, this arrival frequency is an intermediate frequency (IF) when the radio wave S1 reaches the terminal 2020 and is down-converted in the terminal 2020.

23 is an explanatory diagram of the estimated frequency satellite calculating program 2114.

As shown in FIG. 23, the control unit 2100 adds the Doppler shift H2 to the transmission frequency H1 from the GPS satellite 12a or the like and calculates the estimated frequency A2. The outgoing frequency H1 from the GPS satellites 12a and the like is conventional, for example, 1,575.42 MHz.

The Doppler shift H2 occurs according to the relative movement of each GPS satellite 12a and the terminal 2020. The control unit 2100 calculates the line speed (speed relative to the direction of the terminal 2020) of each GPS satellite 12a at the current time in accordance with the epimeris 2152b and the initial position QB0. Then, based on the line speed, the Doppler shift H2 is calculated.

The control unit 2100 calculates an estimated frequency A2 for each GPS satellite 12a or the like that is an observable satellite.

The estimated frequency A2 includes an error equal to the drift of the clock (reference oscillator: not shown) of the terminal 2020. Drift is a change of the oscillation frequency in response to a change in temperature.

For this reason, the control part 2100 searches the radio wave S1 etc. at the frequency of a predetermined | prescribed width centering on the estimated frequency A2. For example, the radio wave S1 or the like is searched for at a frequency of every 100 Hz in the range of a frequency from (A2-100) kHz to (A2 + 100) kHz.

Unlike the second embodiment, when the drift can be estimated in advance, the center frequency for starting the search may be calculated based on the estimated frequency A2 and the estimated drift.

As shown in FIG. 22, the terminal 2020 stores the measurement calculation program 2116 in the first storage unit 2110. The measurement calculation program 2116 includes a C / A code and a terminal received by the control unit 2100 from the GPS satellites 12a and the like in each frequency sequence F1 to F3 for each GPS satellite 12a and the like. 2020) performs correlation processing of the generated replica C / A code to calculate a measurement including the maximum value Pmax of the correlation integration value, the correlation integration value Pnoise of the noise, the candidate code phase, and the reception frequency. One program. The measurement calculation program 2116 and the control unit 2100 are examples of the phase calculation unit, and are also examples of the reception frequency specifying unit.

24A to 24C are explanatory diagrams of the measurement calculation program 2116.

As shown in FIG. 24A, the control unit 2100 divides one chip of the C / A code into equal intervals, for example, by the base band unit 2032b to perform a correlation process. One chip of the C / A code is divided into 32 equal parts, for example. That is, correlation processing is performed at intervals of the phase width (first phase width W1) of one third of the chip. The phase of the interval of the first phase width W1 when the control unit 2100 performs a correlation process is referred to as a first sampling phase SC1.

The first phase width W1 is defined as the phase width that can detect the correlation maximum value Pmax when the signal strength when the radio wave S1 or the like reaches the terminal 2020 is -155 dBm or more. . Simulation results show that the correlation maximum value Pmax can be detected even with a weak electric field if the signal width is -155 dBm or more with a phase width of 1/32 chips.

As shown in FIG. 24B, the control part 2100 performs a correlation process centering on the estimated frequency A2, shifting the frequency range of +/- 100kHz by 1st phase width W1. At this time, correlation processing is performed while shifting the frequency by 100 Hz.

As shown in FIG. 24C, the correlation value integration P corresponding to the phases C1 to C64 for two chips is output from the base band portion 2032b. Each phase C1 to C64 is the first sampling phase SC1.

The control unit 2100 searches, for example, from the first chip to the first chip of the C / A code based on the measurement calculation program 2116.

The control unit 2100 calculates the code phase CPB1, the reception frequencies fB1, PBmax1, and PBnoise1 in each frequency sequence F1 to F3 for each GPS satellite 12a, and the like, and present measurement information 2160. ) The code phase CPB1 and the reception frequencies fB1, PBmax1 and PBnoise1 are collectively called a measurement.

The code phase CPB1 is converted into distances. As described above, since the code length of the C / A code is 300 km (km), for example, the code phase which is the singular part of the C / A code can be converted into a distance.

25 is a diagram illustrating an example of the current measurement information 2160.

As shown in FIG. 25, the current measurement information 2160 shows the frequency fB11a and code phases CPB11a, PBmax11a, and PBnoise11a in the frequency sequence F1, for example with respect to the GPS satellite 12a. It is shown.

The current measurement information 2160 indicates the frequency fB12a and the code phases CPB12a, PBmax12a, and PBnoise12a in the frequency sequence F2 with respect to the GPS satellite 12a.

The current measurement information 2160 indicates the frequency fB13a and the code phases CPB13a, PBmax13a, and PBnoise13a in the frequency sequence F3 with respect to the GPS satellite 12a.

The frequencies fB11a to fB13a are reception frequencies when the radio wave S1 from the GPS satellite 12a is received.

Similarly, the current measurement information 2160 indicates a frequency f11b or the like (not shown) in the frequency sequence F1 to the frequency sequence F3 and the like with respect to the GPS satellites 12b to 12f.

In addition, the measurement in the same frequency series F1 etc. with respect to the same GPS satellite 12a etc. is called a corresponding measurement. For example, the code phase CPB11a and the frequency fB11a in the frequency sequence F1 with respect to the GPS satellite 12a are corresponding measures.

In addition, unlike the second embodiment, as a method of correlation processing, a narrow correlator (for example, see Japanese Patent Laid-Open No. 2000-312163) may be employed.

As shown in FIG. 22, the terminal 2020 stores the measurement storage program 2118 in the first storage unit 2110. The measurement storage program 2118 is a program for the control unit 2100 to save the measurement in the second storage unit 2150.

The control unit 2100 stores the new measurement as the current measurement information 2160 in the second storage unit 2150, and stores the existing current measurement information 2160 as the previous measurement information 2162. The data is stored in the storage unit 2150. The previous measurement information 2162 includes the code phase CPB0 and the frequencies fB0, PBmax0, and PBnoise0 at the time of the previous positioning.

FIG. 26 is a diagram illustrating the previous measurement information 2162.

As shown in FIG. 26, last measurement information 2162 has shown the frequency fB01a etc. which were computed in each frequency series F1 to F3 for each GPS satellite 12a etc., respectively. In addition, in FIG. 26, only the measurement about GPS satellite 12a is shown, and the illustration of other GPS satellites 12b etc. is abbreviate | omitted.

As shown in FIG. 22, the terminal 2020 stores the frequency evaluation program 2120 in the first storage unit 2110. The frequency evaluating program 2120 allows the control unit 2100 to determine whether the frequency difference between the reception frequency fB0 at the last positioning and the reception frequency fB1 at the current positioning is equal to or less than the frequency threshold α2. Program. The range below the frequency threshold (alpha) 2 is prescribed | regulated by the threshold value less than the frequency interval of the frequency series F1, F2, and F3. As described above, if the frequency interval is 50 hertz (Hz), the frequency threshold α2 is, for example, 30 hertz (Hz).

The frequency evaluation program 2120 and the control unit 2100 described above are examples of the frequency difference evaluation unit. The range below the frequency threshold α2 is an example within the frequency difference allowable range predefined.

The control unit 2100 makes the above-described determination with respect to all code phases CPB11a and the like (refer to FIG. 25) shown in the current measurement information 2160. For example, it is determined whether or not the frequency difference between the current frequency fB11a and the previous frequency fB01a with respect to the GPS satellite 12a is equal to or less than the frequency threshold α2. Similarly, it is determined whether or not the frequency difference between the frequency fB12a and the frequency fB02a is equal to or less than the frequency threshold α2, and whether or not the frequency difference between the frequency fB13a and fB03a is equal to or less than the frequency threshold α2. To judge. Similarly, the GPS satellites 12b to 12f are also subjected to frequency determination.

The terminal 2020 does not use the corresponding code phase CPB11a or the like for positioning when the frequency difference is not equal to or less than the frequency threshold α2. That is, the frequency evaluation program 2120 and the control unit 2100 are examples of the phase exclusion unit.

As shown in FIG. 22, the terminal 2020 stores the predictive code phase program 2122 in the first storage unit 2110. In the predictive code phase program 2122, the control unit 2100 uses the code phase CPB0 during the last positioning, the Doppler shift such as the radio wave S1, and the elapsed time dt from the last positioning. It is a program for predicting the current phase and calculating a predictive code phase (CPBe). Prediction code phase CPBe is an example of a prediction phase. The predictive code phase program 2122 and the control unit 2100 are examples of the predictive phase calculator. The control unit 2100 calculates the prediction code phase CPBe for each frequency sequence F1 to F3 for each GPS satellite 12a or the like.

The prediction code phase CPBe is converted into distances.

27 is an explanatory diagram of a predictive code phase program 2122.

As shown in FIG. 27, the control part 2100 calculates prediction code phase CPBe by Formula 2, for example.

As shown in Formula 2, the control part 2100 elapses time from the last positioning time from the code phase CPB0 at the last positioning to the relative movement speed of the GPS satellite 12a and the terminal 2020, for example. By subtracting the value multiplied by (dt), the prediction code phase CPBe is calculated.

In addition, in Formula 2, prediction code phase CPBe and last code phase CPB0 are converted into distance.

Here, the radio wave S1 and the like propagate at the light beam. For this reason, by dividing the luminous flux by the transmission frequency H1 such as the radio wave S1, it is possible to calculate the approximate speed corresponding to one hertz (Hz) of the Doppler shift. In other words, a Doppler shift of plus (+) 1 hertz (Hz) means that the GPS satellite 12a is approaching the terminal 2020 at 0.19 meters per second (m / s). For this reason, the prediction code phase CPBe becomes shorter than the code phase CPB0 at the time of last positioning. Here, the Doppler shift is, for example, the difference between the frequency fB0 at the time of last positioning and the outgoing frequency H1.

On the other hand, the Doppler shift is negative one-hertz (Hz) because the GP S satellite 12a is moving away from the terminal 2020 at 0.19 meters per second (m / s). For this reason, prediction code phase CPBe becomes longer than code phase CPB0 at the time of last positioning.

In addition, Formula 2 is satisfied on the conditions that the elapsed time from last positioning time is a short time. In other words, equation 2 holds as long as the relationship between the code phase and the elapsed time can be represented as a straight line on the graph.

In addition, unlike the second embodiment, the average value of the difference between the frequency fB0 and the outgoing frequency H1 at the last positioning and the difference between the frequency fB1 and the outgoing frequency H1 at the current positioning is determined. You may make it easier. As a result, the prediction code phase CPBe can be calculated more accurately.

In addition, unlike the second embodiment, the control unit 2100 is the code phase CPB0 at the time of the last positioning, and the prediction code is performed using the code phase CPB0 at the completion of the correlation process. The phase CPBe may be calculated. Since the code phase CPB0 at the completion of the correlation process has a higher level of accuracy than the code phase at the start of the correlation process or the process of the correlation process because the noise is canceled by integration, The precision is also increased.

The control unit 2100 stores the predictive code phase information 2164 indicating the calculated predictive code phase CPBe in the second storage unit 2150.

28 is a diagram illustrating an example of the prediction code phase information 2164.

As illustrated in FIG. 28, the prediction code phase information 2164 is, for example, in the prediction code phase CPBe1a and the frequency sequence F2 in the frequency sequence F1 with respect to the GPS satellite 12a. The prediction code phase CPBe2a and the prediction code phase CPBe3a in the frequency sequence F3 are shown. Similarly, the predictive code phase information 2164 indicates the predictive code phase CPBe1b and the like (not shown) in each of the frequency sequences F1 to F3 in the GPS satellites 12b to 12f.

As shown in FIG. 22, the terminal 2020 stores the code phase evaluation program 2124 in the first storage unit 2110. In the code phase evaluation program 2124, the control unit 2100 determines that the code phase difference between the current code phase CPB1 and the predictive code phase CPBe is a code phase threshold β2 (hereinafter, “threshold β2”). It is a program for judging whether or not it is. The range below the threshold value β2 is an example within the phase difference tolerance range. The code phase evaluation program 2124 and the control unit 2100 are examples of the phase difference evaluation unit.

The control unit 2100 uses the code phase CPB1 corresponding to the frequency difference determined by the above-described frequency evaluation program 2120 to be equal to or less than the threshold value α2, to be subjected to the determination based on the code phase evaluation program 2124. do.

If the code phase difference is less than or equal to the threshold value β2 for each frequency series F1 to F3 such as each GPS satellite 12a based on the code phase evaluation program 2124, the control unit 2100 Phase difference evaluation pass number of times (henceforth "pass number of times") is added one by one. The control unit 2100 sets the number of passes to zero when the code phase difference is larger than the threshold value β2 for each frequency series F1 to F3 such as each GPS satellite 12a.

The control unit 2100 stores the code phase evaluation path count information 2166 indicating the number of passes in the second storage unit 2150.

As shown in FIG. 22, the terminal 2020 stores the code phase selection program 2126 in the first storage unit 2110. In the code phase selection program 2126, the control unit 2100 has a minimum code phase difference for each GPS satellite 12a or the like among the code phases CPB1 corresponding to the code phase difference that is equal to or smaller than the threshold value β2 described above. It is a program for selecting code phases CPB1 to select code phases CP1s. The selection code phases CP1s are an example of selection phases. The code phase selection program 2126 and the control unit 2100 are examples of the phase selection unit.

29 is an explanatory diagram of the code phase selection program 2126.

As shown in FIG. 29, the control unit 2100 calculates, for example, the absolute value dCPB11a of the difference between the code phase CPB11a and CPBe1a in the frequency sequence F1 with respect to the GPS satellite 12a. The control unit 2100 further includes an absolute value dCPB12a of the difference between the code phase CPB12a and CPBe2a in the frequency sequence F2, and an absolute value ddBB13a of the difference between the code phase CPB13a and CPBe3a in the frequency sequence F3. ) Is calculated.

For example, as shown in FIG. 29, when the absolute value dCPB11a is the minimum among the absolute values dCPB11a to dCPB13a, the code phase CPB11a is selected.

The control unit 2100 sets the code phase CPB11a as the selection code phase CP1sa.

The control unit 2100 performs the above-described selection for each GPS satellite 12a and the like, respectively.

The control unit 2100 stores the selection code phase information 2168 indicating the selected selection code phases CP1s in the second storage unit 2150.

30 is a diagram illustrating an example of the selection code phase information 2168.

The selection code phase information 2168 indicates a code phase calculated in any one of the frequency sequences F1 to F3 for each GPS satellite 12a or the like.

As shown in FIG. 22, the terminal 2020 stores the selection code phase first evaluation program 2128 in the first storage unit 2110. The selection code phase first evaluation program 2128 is a program for the control unit 2100 to determine whether the signal strength XPR such as the selection code phase CP1sa is the maximum. The selection code phase first evaluation program 2128 and the control unit 2100 are examples of the selection phase first evaluation unit.

Specifically, the control unit 2100 determines whether the XPR of the selection code phase CP1sa is the maximum among the code phases CPB1 and the like for each GPS satellite 12a or the like.

As shown in FIG. 22, the terminal 2020 stores the selection code phase second evaluation program 2130 in the first storage unit 2110. The selection code phase second evaluation program 2130 is a program for the control unit 2100 to determine whether the number of passes described above is γ times or more. (gamma) times is three times, for example, and is prescribed | regulated previously. The range of γ or more times is an example within a prescribed frequency range. The selection code phase second evaluation program 2130 and the control unit 2100 are examples of the selection phase second evaluation unit.

The number of passes becomes zero unless the code phase difference is equal to or less than the threshold β2, so that the number of passes is γ or more times in succession that the code phase is continuously equal to or less than the threshold β2. It means more than times.

In addition, the selection code phase second evaluation program 2130 is also a program for the control unit 2100 to determine whether or not the number of times the XPR decreases during integration time is 10 or more times, for example, previously defined. Do.

Specifically, when the control unit 2100 determines that the signal strength XPR such as the selection code phase CP1sa is not maximum by the selection code phase first evaluation program 2128 described above, the selection code phase agent is selected. The judgment by 2 evaluation programs 2130 is performed.

31A to 31C are explanatory diagrams of the selection code phase second evaluation program 2130.

As shown in FIG. 31A, for example, when integration time is made into 16 second (s), XPR in 16 second (s) elapses (integration completion) is the largest. This is because noises cancel each other, while C / A codes are integrated. The code phase at the time of completion of integration is highly reliable.

And in theory, XPR becomes large from the time of integration start to the time of integration completion.

By the way, as in FIG. 31B, XPR may be reduced immediately after integration start. For this reason, the code phase cannot be calculated correctly.

When the signal received by the terminal 2020 is noise (upper signal), as shown in FIG. 31C, even when the integration is completed, the XPR does not increase. For this reason, it is difficult to calculate a code phase.

As described above, whether the received radio wave is a radio wave carrying a C / A code or noise, the XPR may be small immediately after the start of integration, and the XPR may decrease. In the case where the received radio wave is a radio wave carrying a C / A code, the XPR increases as the integration time elapses.

For this reason, after a considerable amount of time has elapsed since the start of integration, when the state where the code phase difference is equal to or less than the threshold value β2 is continued, it can be considered that the received signal is not noise.

Moreover, when the fall of XPR generate | occur | produces even if a considerable time continues from the start of integration time, it can be considered that the received signal is noise. In other words, when a decrease in XPR does not occur after a considerable time continues from the start of integration time, it means that the received signal is considered to be not noise.

Therefore, in the terminal 2020, it is determined whether or not the state in which the code phase difference is equal to or less than the threshold value β2 continues, and whether the degradation of the XPR continues, or whether the received signal is noise. It is a standard for.

As shown in FIG. 22, the terminal 2020 stores the positioning program 2132 in the first storage unit 2110. The positioning program 2132 is performed by the control unit 2100 when the determination result by the selection code phase first evaluation program 2128 or the selection code phase second evaluation program 2130 is positive. Is a program for positioning the current position using the positioning use code phase (CPB1f). That is, the positioning program 2132 and the control unit 2100 are examples of the positioning unit.

For example, when the XPR of the selection code phase CP1sa is maximum, the control unit 2100 sets the selection code phase CP1sa to the positioning use code phase CPB1fa.

The control unit 2100 selects code phases CP1sa when the number of code phase evaluation passes is γ or more and the XPR is less than 10 times even when the XPR of the selection code phase CP1sa is not the maximum. Denotes the positioning use code phase (CPB1fa).

On the other hand, when the XPR of the selection code phase CP1sa is not the maximum, the control unit 2100 selects the selection code when the number of code phase evaluation passes is less than γ times or when the XPR reduction is 10 or more times. Of the code phases CPB12a and CP13a other than the phases CP1sa (code phase CPB11a), the larger XPR is used as the positioning use code phase CPB1fa.

The control unit 2100 stores the positioning use code phase information 2170 indicating the determined positioning use code phase CPB1f in the second storage unit 2150.

32 is a diagram illustrating an example of the positioning use code phase information 2170.

As shown in Fig. 32, the positioning use code phase information 2170 indicates, for example, positioning use code phases CPB1fa, CPB1fb, CPB1fc, and CPB1fd corresponding to the GPS satellites 12a, 12b, 12c, and 12d, respectively. Information to indicate.

The control unit 2100 calculates the current position Q1 using the positioning use code phases CPB1fa, CPB1fb, CPB1fc, and CPB1fd shown in the positioning use code phase information 2170.

The control unit 2100 stores the positioning position information 2172 indicating the calculated positioning position QB1 in the second storage unit 2150.

As shown in FIG. 22, the terminal 2020 stores the positioning position output program 2134 in the first storage unit 2110. The positioning position output program 2134 is a program for the control unit 2100 to display the positioning position QB1 on the display device 2034 (see FIG. 20).

The terminal 2020 is configured as described above.

The terminal 2020 may determine whether the code phase difference is equal to or less than the threshold β2. That is, the terminal 2020 can verify the accuracy of the code phase CPB1.

In addition, among the code phases CPB1 corresponding to the code phase difference whose code phase difference is equal to or less than the threshold β2, the terminal 2020 selects the code phase CPB1 having the minimum code phase difference for each GPS satellite 12a or the like. The selection code phases (CP1s) can be selected. The select code phases CP1s are higher than the code phases CPB1 of other frequency sequences because they are the code phases with the smallest code phase difference.

In addition, the terminal 2020 may determine whether the signal strength XPR of the selection code phase CP1s is maximum. If the XPR of the selection code phases CP1s is maximum, it can be considered that the selection code phases CP1s are guaranteed to have higher precision than the other code phases CPB1.

When the determination result by the selection code phase first evaluation program 2128 is affirmative, the terminal 2020 determines the current position by using the selection code phase CP1s as the positioning use code phase CPB1f. Can be.

For this reason, the terminal 2020 can carry out positioning with high precision, after verifying the precision of the phase of a positioning base code under the weak electric field with a weak radio wave strength.

In addition, since the terminal 2020 has the selection code phase second evaluation program 2130, the code phases in the frequency sequences F1 to F3 to which the selection code phases CP1s belong are continuously the threshold value β2. When the number of times used is less than three times, the current position can be measured using the selection code phases CP1s.

The frequency sequence F1 to which the selection code phase CP1s belongs is that the number of times the code phase in the frequency sequence F1 to which the selection code phase CP1s belongs is three times or more that is equal to or less than the threshold value β2 in succession. The code phase in the example means higher precision than the code phase in other frequency sequences.

For this reason, even when the determination result by the selection code phase 1st evaluation program 2128 is negative, the terminal 2020 can perform positioning using the code phase with high precision.

In addition, the terminal 2020 can exclude the code phase CPB1 corresponding to the frequency fB1 outside the range within the frequency threshold α2 from positioning.

This means that the terminal 2020 can not only verify the accuracy of the code phase CPB1 of the C / A code but also verify the accuracy of the reception frequency fB1 when calculating the code phase CPB1. do.

For this reason, the terminal 2020 can perform positioning with more precision, after verifying the precision of the code phase of positioning base code under the weak electric field with weak signal strength.

As mentioned above, although the structure of the terminal 2020 which concerns on 2nd Embodiment is mentioned, the operation example is demonstrated mainly using FIG.

33 is a schematic flowchart showing an operation example of the terminal 2020.

First, the terminal 2020 receives the radio wave S1 and the like and calculates the measurement (step S201 in FIG. 33). This step S201 is an example of a phase calculation step.

Subsequently, the terminal 2020 stores the measurement (step S202).

Subsequently, the terminal 2020 determines whether or not the absolute value of the frequency difference between the current frequency fB1 and the previous frequency fB0 is equal to or less than the frequency threshold α2 (step S203).

In step S203, the terminal 2020 does not use the code phase CPB1 corresponding to the frequency difference determined to be less than or equal to the frequency threshold value α2 (step S211).

In contrast, in step S203, for the code phase CPB1 corresponding to the frequency difference determined as equal to or less than the frequency threshold α2, the corresponding prediction code phase CPBe is calculated (step S204). This step S204 is an example of the prediction phase calculation step.

Subsequently, the terminal 2020 determines whether the absolute value of the code phase difference between the code phase CPB1 and the predictive code phase CPBe is equal to or less than the threshold β2 (step S205). This step S205 is an example of a phase evaluation step.

In step S205, the terminal 2020 does not use the code phase CPB1 corresponding to the code phase difference determined not to be less than or equal to the threshold value β2 (step S211).

On the other hand, in step S205, the terminal 2020 has a minimum code phase for each GPS satellite 12a or the like with respect to the code phase CPB1 corresponding to the code phase difference determined not to be less than or equal to the threshold β2. The code phase CPB1 corresponding to the difference is selected, and the selection code phase CP1s is set (step S206). This step S206 is an example of a phase selection step.

Subsequently, the terminal 2020 determines the positioning use code phase CPB1f (step S207).

Here, using step 34, the details of step S207 will be described as an example of determining whether or not the selection code phase CP1sa in the positioning sequence F1 of the GPS satellite 12a is used for positioning. do.

34 is a flowchart showing details of step S207.

First, the terminal 2020 determines whether the XPR of the selection code phase CP1sa is maximum (step S221 of FIG. 34). This step S221 is an example of the selection phase first evaluation step.

If the determination in step S221 is affirmative, the terminal 2020 determines the selection code phase CP1sa as the positioning use code phase CPB1fa (step S224).

In contrast, when the evaluation in step S221 is negative, the terminal 2020 determines whether the number of passes of the code phase evaluation in the frequency sequence F1 is three or more times (step S222). This step S222 is an example of the selective phase second evaluation step.

When the determination in step S222 is affirmative, the terminal 2020 determines whether or not the number of times of XPR reduction of the frequency sequence F1 is less than ten (step S223).

In step S223, the terminal 2020 determines that the selection code phase CP1sa is the positioning use code phase CPB1fa when determining that the number of XPR decreases of the frequency sequence F1 is less than ten (step S224). .

On the other hand, when the terminal 2020 judges that the evaluation in step S222 was negative, or it is determined in step S223 that the number of XPR decreases of the frequency series F1 is not less than 10 times, CP12a or CP13a, It is determined as positioning use code phase CPB1fa that the XPR is maximum (step S225).

The terminal 2020 performs each step S221 to step S2 25 described above for each GPS satellite 12a and the like.

Subsequently, the terminal 2020 determines whether or not there are three or more positioning use code phases CPB1f (step S208).

In step S208, when the terminal 2020 determines that the positioning use code phase CPB1f is less than three, since positioning is impossible, it ends without positioning.

In contrast, in step S206, when the terminal 2020 determines that there are three or more positioning use code phases CPB1f, the terminal 2020 performs positioning using the positioning use code phases CPB1f (step S209). This step S209 is an example of the positioning step.

Subsequently, the terminal 2020 outputs the positioning position QB1 (see FIG. 22) (step S210).

According to the above steps, the terminal 2020 can perform positioning with high accuracy after verifying the accuracy of the phase of the positioning base code under a weak electric field having a weak signal strength.

[Third embodiment]

35 is a schematic diagram illustrating the terminal 3020 and the like of the third embodiment.

As shown in FIG. 35, the terminal 3020 is radio wave (S1, S2, S3, S4) from GPS satellites 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h which are positioning satellites, for example. , S5, S6, S7 and S8) can be received. The GPS satellites 12a and the like are also examples of sources. In addition, the source may be a satellite positioning system (SPS) satellite and is not limited to the GPS satellite.

Various codes (signs) are carried in the radio wave S1 and the like. One of them is the C / A code (Sca). This C / A code Sca is a signal having a bit rate of 1.023 Mbps and a bit length of 1,023 bits (= 1 msec). The C / A code Sca is composed of 1,023 chips. The terminal 3020 is an example of a positioning device for positioning the current position, and performs positioning of the current position using this C / A code. This C / A code Sca is an example of positioning basic code.

In addition, information on the radio wave S1 and the like includes almanac (Sal) and epimeris (Seh). Almanac (Sal) is information indicating the rough satellite trajectory of all GPS satellites 12a and the like, and Epimeris (Seh) is information indicating the precise satellite trajectory of each GPS satellite 12a and the like. Almanak (Sal) and Epimeris (Seh) are collectively called navigation messages.

The terminal 3020 can, for example, specify the phases of the C / A codes from three or more different GPS satellites 12a or the like to position the current position.

36 is a conceptual diagram illustrating an example of the positioning method.

As shown in FIG. 36, for example, it can be thought that C / A codes are continuously arranged between the GPS satellite 12a and the terminal 3020. As shown in FIG. In addition, since the distance between the GPS satellite 12a and the terminal 3020 is not an integer multiple of the length (300 kilometers (km)) of the C / A code, there is a code-single section (C / Aa). . That is, between the GPS satellite 12a and the terminal 3020, there is an integer multiple of the C / A code and a singular portion. The length of the sum of the integral part and the singular part of the C / A code is a pseudo distance. The terminal 3020 performs positioning using a pseudo distance with respect to three or more GPS satellites 12a and the like.

In this embodiment, the singular part C / Aa of a C / A code is called a code phase. For example, the code phase may be represented by the number of 1,023 chips of the C / A code, or may be expressed in terms of distance. When calculating the pseudo distance, the code phase is converted into a distance.

The position on the orbit of the GPS satellite 12a can be calculated using Epimeris (Seh). For example, if the distance between the position on the orbit of the GPS satellite 12a and the initial position QC0 to be described later is calculated, the integer multiple of the C / A code can be specified. In addition, since the length of the C / A code is 300 kilometers (km), the position error of the initial position QC0 needs to be within 150 kilometers (km).

36, the correlation process is performed, moving the replica C / A code in the direction of arrow X1, for example. At this time, the terminal 3020 performs correlation processing while varying the synchronization frequency. This correlation process consists of a coherent process and an incoherent process mentioned later.

The phase where the correlation integration value is maximum is the code number (C / Aa).

Unlike the third embodiment, the terminal 3020 may perform positioning using, for example, radio waves from the communication base station of the cellular phone. In addition, unlike the third embodiment, the terminal 3020 may receive radio waves from a LAN (Local Area Network) to perform positioning.

37 is an explanatory diagram of correlation processing.

Coherent is a process of correlating a C / A code received by the terminal 3020 with a replica C / A code. The replica C / A code is a code generated by the terminal 3020. The replica C / A code is an example of a replica positioning basic code.

For example, as shown in FIG. 37, if the coherent time is 10 msec, the correlation value of the C / A code and replica C / A code synchronously accumulated in 10 msec time is calculated. As a result of the coherent process, the correlated phase (code phase) and the correlation value are output.

Incoherent is a process of calculating a correlation integration value (incoherent value) by integrating a correlation value of a coherent result.

As a result of the correlation process, the code phase output by the coherent process and the correlation integration value are output.

38 is a diagram illustrating an example of a relationship between a correlation integration value and a code phase.

The code phase CP1 corresponding to the maximum value Pmax of the correlation integration value in FIG. 38 is the code phase of the replica C / A code, that is, the code phase of the C / A code.

For example, the terminal 3020 sets the correlation integration value of the one with the smaller correlation integration value as the correlation integration value Pnoise among the code phases that are one-half chip away from the code phase CP1.

The terminal 3020 defines a value obtained by dividing the difference between Pmax and Pnoise by Pmax as the signal strength XPR. Signal strength XPR is an example of signal strength.

And if the XPR is 0.2 or more, for example, when the XPR is 0.2 or more, the terminal 3020 makes a code phase candidate which uses code phase CP1 for positioning. Hereinafter, this code phase is called "candidate code phase." The candidate code phase is a candidate used for positioning, and the terminal 3020 may not be limited to actually used for positioning.

39 and 40 are diagrams showing an example of the relationship between the candidate code phase and time lapse.

39 shows a state where the GPS satellite 12a is nearing the terminal 3020, for example.

When the GPS satellite 12a approaches the terminal 3020, since the distance between the GPS satellite 12a and the terminal 3020 becomes short, the candidate code phase C1 approaches 0 with time.

The synchronization frequency F1 is set to increase with time. This is because the Doppler shift caused by the GPS satellite 12a nearing the terminal 3020 increases the frequency at which the radio wave S1 reaches the terminal 3020.

The terminal 3020 uses, for example, three frequency sequences F1, F2, and F3, as shown in FIG. The frequency series F1 and the like are examples of frequency series. The frequency series F1 and F2 are separated by a frequency width of 50 hertz (Hz). In addition, the frequency series F1 and F3 are separated by a frequency width of 50 hertz (Hz). A frequency interval of 50 hertz (Hz) is predefined. In other words, the frequency interval of 50 hertz (Hz) is an example of the frequency interval. This frequency interval is prescribed in less than the step interval of the frequency search in the correlation process performed by the terminal 3020. For example, if the step interval of the frequency search is 100 hertz (Hz) (see Fig. 45B), it is prescribed in less than 100 hertz (Hz).

The frequency sequence F1 or the like may be a plurality, and, unlike the third embodiment, for example, four or more may be used.

As shown in FIG. 40, each frequency series F1 etc. is set so that it may change with time over anticipation of the Doppler shift of arrival frequency.

And any one of each frequency series F1 etc. will follow the Doppler shift of arrival frequency most accurately.

In the frequency series F1, the code phase C1 is calculated. In the frequency sequence F2, the code phase C2 is calculated. In the frequency sequence F3, the code phase C3 is calculated.

As described above, the three code phases C1 and the like are calculated in parallel, but it can be assumed that the candidate code phases calculated with the highest signal strength XPR have the highest reliability.

By the way, it cannot be limited that XPR maintains the highest frequency series F1 and the like. For example, as shown in FIG. 40, for example, between time t1 and t2, XPR of the candidate code phase C1 calculated with the frequency series F1 is the highest, and between time t2 and t3. In this case, the XPR of the candidate code phase C2 calculated by the frequency series F2 is the highest.

Based on the expected Doppler shift, the frequencies of each frequency series F1 and the like are changed, so that the candidate code phase calculated by one frequency series is continuously compared to the candidate code phases calculated by another frequency series. The precision will be high. In other words, for example, the frequency sequence F1 will continue to follow the actual reached frequency most accurately than the other frequency sequences F2 and F3.

For this reason, when the frequency sequence is changed over time, the candidate code phase calculated in the state of high XPR is not limited to the highest accuracy.

In this regard, the terminal 3020 can perform positioning with high accuracy after verifying the precision of the candidate code phase under the weak electric field by the following hardware configuration and software configuration.

(About main hardware configuration of terminal 3020)

41 is a schematic diagram showing a main hardware configuration of the terminal 3020.

As shown in FIG. 41, the terminal 3020 has a computer, and the computer has a bus 3022. A central processing unit (CPU) 3024, a memory device 3026, and the like are connected to the bus 3022. The storage device 3026 is, for example, a random access memory (RAM), a read only memory (ROM), or the like.

In addition, an input device 3028, a power supply device 3030, a GPS device 3032, a display device 3034, a communication device 3036, and a clock 3038 are connected to the bus 3022.

(About the structure of GPS device 3032)

37 is a schematic diagram showing the configuration of the GPS device 3032.

As shown in FIG. 37, the GPS device 3032 includes an RF unit 3032a and a baseband unit 3032b.

The RF unit 3032a receives the radio wave S1 and the like through the antenna 3033a. The LNA 3033a, which is an amplifier, amplifies a signal such as a C / A code carried in the radio wave S1. Then, the mixer 3033c down-converts the frequency of the signal. An orthogonal (IQ) detector 3033d then IQ separates the signal. Subsequently, the A / D converters 3033e1 and 3033e2 are configured to convert the IQ separated signals into digital signals, respectively.

The base band section 3032b is configured to receive a signal converted into a digital signal from the RF section 3032a, sample and integrate the signal, and take the correlation of the C / A code held by the base band section 3032b. have. The base band unit 3032b has, for example, 128 correlators (not shown) and accumulators (not shown), and is capable of performing correlation processing in 128 phases at the same time. The correlator is a configuration for performing the coherent process described above. The accumulator is a configuration for performing the incoherent process described above.

(About main software configuration of terminal 3020)

43 is a schematic diagram showing the main software configuration of the terminal 3020.

As shown in FIG. 43, the terminal 3020 includes a control unit 3100 for controlling each unit, a GPS unit 3102 corresponding to the GPS device 3032 of FIG. 41, and a time unit 3104 corresponding to the clock 3038. Has a back.

The terminal 3020 further includes a first storage unit 3110 for storing various programs and a second storage unit 3150 for storing various kinds of information.

As shown in FIG. 43, the terminal 3020 stores the navigation message 3152 in the second storage unit 3150. The navigation message 3152 includes almanac 3152a and epimeris 3152b.

The terminal 3020 uses the almanac 3152a and the epimeris 3152b for positioning.

As shown in FIG. 43, the terminal 3020 stores the initial positional information 3154 in the second storage unit 3150. The initial position QC0 is, for example, the last positioning position.

As shown in FIG. 43, the terminal 3020 stores the observable satellite calculation program 3112 in the first storage unit 3110. The observable satellite calculation program 3112 is a program for the control unit 3100 to calculate the observable GPS satellite 12a and the like on the basis of the initial position QC0 shown in the initial position information 3154.

Specifically, the control unit 3100 determines the GPS satellite 12a or the like that can be observed at the current time measured by the timekeeping unit 3104 with reference to the almanac 3152a. The control unit 3100 stores the observable satellite information 3156 indicating the observable GPS satellite 12a or the like (hereinafter referred to as "observable satellite") in the second storage unit 3150. In the third embodiment, the observable satellites are GPS satellites 12a to 12h (see FIGS. 35 and 43).

As shown in FIG. 43, the terminal 3020 stores the estimated frequency calculating program 3114 in the first storage unit 3110. The estimated frequency calculation program 3114 is a program for the control unit 3100 to estimate a reception frequency such as the radio wave S1 from the GPS satellite 12a or the like.

This reception frequency is the arrival frequency when the radio wave S1 reaches the terminal 3020. More specifically, this reception frequency is an intermediate frequency (IF) when the radio wave S1 reaches the terminal 3020 and is down-converted in the terminal 3020.

44 is an explanatory diagram of the estimated frequency calculating program 3114.

As shown in FIG. 44, the control unit 3100 adds the Doppler shift H2 to the transmission frequency H1 from the GPS satellite 12a or the like to calculate the estimated frequency A3. The outgoing frequency H1 from the GPS satellites 12a and the like is conventional, for example, 1,575.42 MHz.

The Doppler shift H2 is generated by the relative movement of each GPS satellite 12a and the terminal 3020. The control unit 3100 calculates the line speed (speed relative to the direction of the terminal 3020) of each GPS satellite 12a at the current time based on the epimeris 3152b and the initial position QC0. Then, based on the line speed, the Doppler shift H2 is calculated.

The control unit 3100 calculates an estimated frequency A3 for each GPS satellite 12a or the like that is an observable satellite.

In addition, the estimated frequency A3 includes an error equal to the drift of the clock (reference oscillator: not shown) of the terminal 3020. Drift is a change in oscillation frequency due to temperature change.

For this reason, the control part 3100 searches the radio wave S1 etc. at the frequency of the predetermined | prescribed width centering on the estimated frequency A3. For example, the radio wave S1 or the like is searched for at a frequency of 100 Hz from a frequency range of (A3-100) kHz to a frequency of (A3 + 100) kHz.

As shown in FIG. 43, the terminal 3020 stores the measurement calculation program 3116 in the first storage unit 3110. In the measurement calculation program 3116, the control unit 3100 performs a correlation process between the C / A code received from the GPS satellite 12a and the like and the replica C / A code generated by the terminal 3020, and the correlation integration value. Is a program for calculating a measurement including a maximum value Pmax, a correlation integration value Pnoise of noise, a candidate code phase, and a reception frequency. The measurement calculation program 3116 and the control unit 3100 are examples of the phase calculation unit, and are examples of the reception frequency specifying unit.

45A to 45C are explanatory diagrams of the measurement calculation program 3116.

As shown in FIG. 45A, the control unit 3100 divides one chip of the C / A code into equal intervals, for example, by the base band unit 3032b to perform a correlation process. One chip of the C / A code is divided into 32, for example. That is, correlation processing is performed at intervals of the phase width (first phase width W1) of one third of the chip. The phase of the interval of the first phase width W1 when the control unit 3100 performs correlation processing is referred to as a first sampling phase SC1.

The first phase width W1 is defined as the phase width at which the correlation maximum value Pmax can be detected when the signal strength when the radio wave S1 or the like reaches the terminal 3020 is -155 dBm or more. . Simulation results show that the correlation maximum value Pmax can be detected even with a weak electric field if the signal width is -155 dBm or more with a phase width of 1/32 chips.

As shown in FIG. 45B, the control part 3100 performs a correlation process centering on estimated frequency A3, shifting the frequency range of +/- 100 kHz by 1st phase width W1. At this time, correlation processing is performed while shifting the frequency by 100 Hz.

As shown in Fig. 45C, the baseband portion 3032b outputs a correlation value integration P corresponding to the phases C1 to C64 for two chips. Each phase C1 to C64 is the first sampling phase SC1.

The control unit 3100 searches, for example, from the first chip to the first chip of the C / A code based on the measurement calculation program 3116.

The control unit 3100 calculates the XPR based on Pmax and Pnoise, and sets the code phase CPC1 and the reception frequencies fC1, PCmax1, and PCnoise1 corresponding to the state with the largest XPR as the current measurement information 3160. . The code phase CPC1 and the reception frequencies fC1, PCmax1 and PCoise1 are collectively called a measurement. The terminal 3020 calculates a measure for each GPS satellite 12a or the like.

The code phase CPC1 is converted into distances. As described above, the code length of the C / A code is, for example, 300 kilometers (km), so that the code phase, which is the singular part of the C / A code, can also be converted into a distance.

The control part 3100 calculates a measurement with respect to six GPS satellites 12a etc. among the observable satellites, for example. In addition, the measurement about the same GPS satellite 12a etc. is called the corresponding measurement. For example, the code phase CPC1 for GPS satellites 12a and the frequency fC1 for GPS satellites 12a are corresponding measurements. The frequency fC1 is a reception frequency when the radio wave S1 from the GPS satellite 12a is received.

Unlike the third embodiment, as a method of correlation processing, narrow correlates (see, for example, Japanese Patent Laid-Open No. 2000-312163) may be employed.

As shown in FIG. 43, the terminal 3020 stores the measurement storage program 3118 in the first storage unit 3110. The measurement storage program 3118 is a program for the control unit 3100 to save the measurement in the second storage unit 3150.

The control unit 3100 stores the new measurement as the current measurement information 3160 in the second storage unit 3150, and stores the existing current measurement information 3160 as the previous measurement information 3322 as the second. The data is stored in the storage unit 3150. The previous measurement information 3322 includes the code phase CPC0 and the frequencies fC0, PCmax0 and PCnoise0 at the time of the previous positioning.

As shown in FIG. 43, the terminal 3020 stores the frequency evaluation program 3120 in the first storage unit 3110. The frequency evaluating program 3120 allows the control unit 3100 to determine whether or not the frequency difference between the reception frequency fC0 at the last positioning and the reception frequency fC1 at the current positioning is within the frequency threshold α3. Program. The range within the frequency threshold α3 is previously defined by a threshold value less than the frequency interval of the frequency series F1, F2, and F3. As described above, if the frequency interval is 50 hertz (Hz), the frequency threshold α3 is, for example, 30 hertz (Hz). The frequency evaluation program 3120 and the control unit 3100 described above are examples of the frequency difference evaluation unit. The range within the frequency threshold α3 is an example within the frequency difference allowable range predefined.

As shown in FIG. 43, the terminal 3020 stores the predictive code phase calculating program 3122 in the first storage unit 3110. The predictive code phase calculation program 3122 is configured by the control unit 3100 based on the code phase CPC0 at the last positioning, the Doppler shift such as the radio wave S1, and the elapsed time dt from the last positioning. Is a program for estimating the current phase and calculating a predictive code phase (CPCe). The predictive code phase (CPCe) is an example of the predictive phase. The predictive code phase calculating program 3122 and the control unit 3100 are examples of the predictive phase calculating unit.

The prediction code phase CPCe is converted into distances.

46 is an explanatory diagram of a predictive code phase calculating program 3122.

As shown in FIG. 46, the control part 3100 calculates the prediction code phase CPCe by Formula 3, for example.

As shown in Formula 3, the control part 3100 shows the elapsed time from the last positioning time from the code phase CPC0 at the last positioning to the relative movement speed of the GPS satellite 12a and the terminal 3020, for example. The prediction code phase (CPCe) is calculated by subtracting the value multiplied by (dt).

In Equation 3, the prediction code phase CPCe and the previous code phase CPC0 are converted into distances.

Here, the radio wave S1 and the like propagate at the light beam. For this reason, by dividing the luminous flux by the transmission frequency H1 such as the radio wave S1, it is possible to calculate the approximate speed corresponding to one hertz (Hz) of the Doppler shift. In other words, a Doppler shift of plus (+) 1 hertz (Hz) means that the GPS satellite 12a is approaching the terminal 3020 at 0.19 meters per second (m / s). For this reason, prediction code phase CPCe becomes shorter than code phase CPC0 at the time of last positioning. Here, the Doppler shift is, for example, the difference between the frequency fC0 at the time of last positioning and the outgoing frequency H1.

On the other hand, a Doppler shift of minus one hertz (Hz) indicates that the GPS satellite 12a is moving away from the terminal 3020 at 0.19 meters per second (m / s). For this reason, prediction code phase CPCe becomes longer than code phase CPC0 at the time of last positioning.

In addition, Formula 3 is established on the condition that elapsed time from last positioning time is a short time. In other words, Equation 3 holds as long as the relationship between the code phase and the elapsed time can be represented as a straight line on the graph.

In addition, unlike the third embodiment, the average value of the difference between the frequency fC0 and the outgoing frequency H1 at the last positioning and the difference between the frequency fC1 and the outgoing frequency H1 at the current positioning is determined. It may be a side. As a result, the prediction code phase CPCe can be calculated more accurately.

The control unit 3100 stores the predictive code phase information 3164 indicating the calculated predictive code phase CPCe in the second storage unit 3150.

As shown in FIG. 43, the terminal 3020 stores the code phase evaluation program 3124 in the first storage unit 3110. In the code phase evaluation program 3124, the control unit 3100 determines that the code phase difference between the current code phase CPC1 and the predictive code phase CPCe is a code phase threshold β3 (hereinafter, referred to as “threshold value β3”). It is a program for judging whether it is below. The range below the threshold value β3 is an example within the phase difference allowable range. The code phase evaluation program 3124 and the control unit 3100 are examples of the phase difference evaluation unit.

The threshold value β3 is defined in advance. The threshold value β3 is 80 meters (m), for example.

The control unit 3100 uses the code phase CPC1 determined by the above-described frequency evaluation program 3120 as the frequency difference equal to or less than the threshold α3 to be the object of determination based on the code phase evaluation program 3124.

As shown in FIG. 43, the terminal 3020 stores the positioning use code phase determination program 3126 in the first storage unit 3110. The positioning use code phase determination program 3126 has a code phase such as the GPS satellite 12a in which the control unit 3100 is a frequency difference within the frequency threshold α3 and a code phase difference less than or equal to the threshold β3. It is a program for determining (CPC1) and the like as the positioning use code phase (CPC1f).

The code phase CPC1 such as the GPS satellite 12a or the like corresponding to the frequency difference that is not within the frequency threshold α3 is excluded from the positioning without being determined as the positioning use code phase CPC1f. The code phase CPC1 corresponding to the frequency difference within the frequency threshold value α3 and corresponding to the code phase difference less than or equal to the threshold value β3 is used for positioning. That is, the positioning use code phase determination program 3126 and the control unit 3100 are examples of the phase exclusion unit.

In the third embodiment, the positioning use code phases CPC1f are, for example, CPC1fa, CPC1fb, CPC1fc, and CPC1fd corresponding to the GPS satellites 12a, 12b, 12c, and 12d, respectively.

The control unit 3100 stores the positioning use code phase information 3166 indicating the positioning use code phase CPC1f in the second storage unit 3150.

In addition, in this embodiment, using code phase CPC1 for positioning and making code phase CPC1 the positioning use code phase CPC1f are synonymous.

As shown in FIG. 43, the terminal 3020 stores the positioning program 3128 in the first storage unit 3110. The positioning program 3128 is a program for the control unit 3100 to position the current position using the positioning use code phase CPC1f. The positioning program 3128 and the control unit 3100 are examples of positioning units.

The positioning use code phase CPC1f is a code phase CPC1 within the above-described threshold value β3 and the like. In other words, positioning the current position using the positioning use code phase CPC1f is equivalent to positioning the current position using the code phase CPC1 or the like within the threshold value β3.

When there are three or more positioning use code phases CPC1f, the control part 3100 performs positioning of the present position using those positioning use code phases CPC1f, and calculates the positioning position QC1.

The control unit 3100 stores the positioning position information 3168 indicating the calculated positioning position QC1 in the second storage unit 3150.

As shown in FIG. 43, the terminal 3020 stores the positioning position output program 3130 in the first storage unit 3110. The positioning position output program 3130 is a program for the control unit 3100 to display the positioning position QC1 on the display device 3034 (see FIG. 41).

As shown in FIG. 43, the terminal 3020 stores the code phase threshold setting program 3132 in the first storage unit 3110. The code phase threshold setting program 3132 is a program for the control unit 3100 to determine the threshold value β3 based on the reception state of the C / A code. This code phase threshold setting program 3132 and the control part 3100 are an example of a phase difference tolerance range determination part.

47 is an explanatory diagram of the code phase threshold setting program 3132.

The table of FIG. 47 is called a condition table.

The condition table includes drift determinism (130b), number of satellites (130c) in tracking, presence of strong satellites (130d), presence of weak satellites (130e), ratio of weak satellites (130f), weakness ratio (130), and historical integration Time 130h and code phase threshold β3.

Drift determinism (130b), satellite count (130c), strong satellite presence (130d), weak satellite presence (130e), weak satellite ratio (130f), weak satellite ratio (130g), and elapsed integration time 130h is an example of the reception state of the C / A code. The drift determination 130b and the like are collectively referred to as a reception state.

As described above, the condition table includes the positioning mode 130a. The positioning mode 130a includes a normal mode, a high sensitivity mode, and a movement mode.

In the normal mode, when the initial setting of the integration time (incoherent time) is 1 second (s), and the signal strength of the C / A code is weak, the integration time is 4 seconds (s), 8 seconds (s), It is positioning mode to lengthen step by step like 24 seconds (s). The normal mode is a positioning mode suitable for the case where the signal strength input to the antenna 3033a of the GPS device 3032 is, for example, minus 150 dBM or more.

The high sensitivity mode is a positioning mode in which when the initial setting of integration time is 1 second (s) and the signal strength of the C / A code is weak, the integration time is immediately extended to 24 seconds (s). The high sensitivity mode is a positioning mode suitable when the signal strength input to the antenna 3033a of the GPS device 3032 is less than, for example, minus 150 dBM.

The movement mode is a positioning mode in which the initial setting of integration time is fixed at 1 second (s). The movement mode is a positioning mode suitable for the terminal 3020 during movement.

As described above, the condition table includes drift determination 130b. A drift is a frequency change by the temperature change of the reference clock (not shown) of the terminal 3020. The smaller the drift, the higher the accuracy of the measurement calculated by the terminal 3020. This drift can be calculated by preliminary positioning using three or more GPS satellites 12a and the like. By the preliminary positioning, it is possible to calculate the visual error of the terminal 3020. And based on this time error, a drift can be calculated.

The drift determination 130b is information indicating whether or not the terminal 3020 has a frequency error with respect to a set value of the frequency within plus or minus (±) 50 hertz (Hz).

The terminal 3020 determines that the drift is determined (with drift determinism) when the frequency error with respect to the set value of the frequency is within plus or minus (±) 50 hertz (Hz).

In contrast, the terminal 3020 determines that the drift is determined (with drift determinism) when the frequency error is greater than plus or minus (±) 50 hertz (Hz).

The frequency range within plus or minus (±) 50 hertz (Hz) is an example of the drift allowable range predefined.

As described above, the terminal 3020 determines that there is drift determinism when the frequency error with respect to the set value of the frequency is within plus or minus (±) 50 hertz (Hz), but this error range is measured. It is prescribed | regulated in the range below the frequency step (refer FIG. 45B) in calculation.

As described above, the condition table includes the satellite number 130c during tracking. The number of satellites 130c during tracking is the number of GPS satellites 12a and the like in which the terminal 3020 continuously receives radio waves S1 and the like.

As described above, the condition table includes the strong satellite presence 130d. The strong satellite presence 130d indicates whether or not the GPS satellite 12a or the like (hereinafter referred to as "strong satellite") having a signal strength XPR of 0.7 or more exists.

The terminal 3020 determines that there is a strong power when there is even one hard power.

In contrast, the terminal 3020 determines that there is no strength when none of the strengths exist.

As described above, the condition table includes weak satellite presence 130e. The weak satellite presence 130e indicates whether or not a GPS satellite 12a or the like (hereinafter referred to as "weak satellite") having a signal strength XPR of 0.4 or less exists.

The terminal 3020 determines that there is weakness when at least one weakness exists.

In contrast, the terminal 3020 determines that there is no weakness when no weakness exists.

As described above, the condition table includes the strong multiplicity 130f. The strong multiplicity 130f indicates whether the GPS satellites 12a and the like that the terminal 3020 is tracking are all strong satellites.

The terminal 3020 determines "YES" when all the GPS satellites 12a and the like being tracked are strong satellites.

On the other hand, the terminal 3020 determines "NO" when one or more of the GPS satellite 12a etc. which are being tracked are not strong satellites.

As mentioned above, the condition table includes the weak multiplicity 130g. The weak multiplicity 130g indicates whether the GPS satellites 12a and the like that the terminal 3020 is tracking are all weak.

The terminal 3020 determines "YES" when all the GPS satellites 12a and the like being tracked are weak satellites.

In contrast, the terminal 3020 determines that the terminal 3020 is "NO" when one or more of the GPS satellites 12a and the like that are being tracked are not weak.

As described above, the condition table includes the elapsed integration time 130h. The elapsed integration time 130h is whether or not the elapsed time from the start of the incoherent to the present time (hereinafter referred to as the "elapsed integration time") is a time threshold, for example, 12 seconds or less. Indicates. In addition, the elapsed time from the start of the incoherent to the present time has the same meaning as the elapsed time since the start of the correlation process.

The terminal 3020 determines that it is "YES" if the elapsed integration time is 12 seconds (s) or less.

In contrast, when the elapsed integration time is longer than 12 seconds (s), the terminal 3020 determines that "NO".

In addition, as the elapsed integration time is longer, in general, the signal strength XPR is increased, and the accuracy of the code phase CPC1 is also improved. For this reason, a time threshold value is prescribed | regulated according to the precision of the code phase CPC1 required corresponding to positioning precision.

The control unit 3100 sets the code phase threshold β3 based on conditions such as the positioning mode 130a included in the above-described condition table.

For example, as a normal mode, the drift determinism 130b is "is", the number of satellites 130c is 8 or more during tracking, and the strong satellite presence 130d is "is", and the strong satellite majority is When 130f is "YES" and the elapsed integration time 130h is "YES" (Cond1), the code phase threshold value β3 is set to the minimum value, for example, 19 meters (m).

In Cond1, the number of GPS satellites 12a and the like being tracked is sufficiently large, and the signal strength XPR is also good, so that the positioning accuracy is improved by setting the code phase threshold β3 small.

In addition, Cond7 has fewer satellites during tracking than in Cond1. In this case, the terminal 3020 sets the code phase threshold value β3 to, for example, 52 meters (m) larger than Cond1. This deteriorates positioning accuracy compared to Cond1, but ensures as many GPS satellites as possible for positioning.

As described above, the terminal 3020 sets the code phase threshold β3 to be smaller as the number of GPS satellites 12a or the like being tracked is smaller when the same reception state, and the smaller the number of GPS satellites 12a or the like being tracked is coded. The phase threshold value β3 is set to be large.

For example, in Cond3, since the elapsed integration time 130h is "NO", the precision of the code phase CPC1 is worse than Cond1. For this reason, the terminal 3020 sets the code phase threshold value β3 slightly larger than Cond1, for example, 25 meters (m), thereby minimizing the deterioration of the positioning accuracy and minimizing the number of possible code phases ( CPC1) can be secured.

For example, in Cond11, the number of satellites in tracking may be three, which is the minimum number for positioning, and the code phase threshold (β3) because the weakness multiplicity 130g is "YES". ), The number of GPS satellites 12a and the like may not reach the number that can be measured. For this reason, the terminal 3020 secures the number of code phases (CPC1) which can be measured while ensuring the deterioration of positioning accuracy to an allowable limit by setting to 80 meters (m) larger than Cond1, Cond4, etc., for example. It is supposed to be.

In addition, in 3rd Embodiment, the maximum value of the code phase (beta) is set to 80 meters (m). The length of this 80 meters (m) is at the time of the last positioning when the terminal 3020 is positioned at the interval of one second (s) while being mounted on the Shinkansen, for example, a high speed moving unit and moving. It is prescribed | regulated as length less than the distance which a code phase changes between time.

For example, in Cond23, since it is a moving mode, the arrival frequency of the radio wave S1 etc. which reaches the terminal 3020 continuously fluctuates in order for the terminal 3020 to move. In addition, it is difficult to calculate the fluctuation of the arrival frequency. For this reason, the terminal 3020 sets the code phase threshold value β3 larger than Cond1, Cond4, etc., for example, 80 meters (m), so that even if the positioning accuracy deteriorates to the allowable limit, the number of codes that can be measured The phase CPC1 is secured.

The terminal 3020 is configured as described above.

The terminal 3020 may determine whether the code phase difference between the current code phase CPC1 and the predictive code phase CPCe is equal to or less than a predetermined threshold value β3. For this reason, the terminal 3020 can verify the precision of the code phase CPC1.

In addition, the terminal 3020 can position the current position by using the code phase CPC1 corresponding to the code phase difference equal to or less than the threshold β3.

For this reason, the terminal 3020 can perform the positioning with high accuracy after verifying the precision of the code phase of the positioning basic code under a weak electric field having a weak signal strength.

In addition, the terminal 3020 can exclude the code phase CPC1 corresponding to the frequency fC1 outside the range within the frequency threshold α3 from positioning.

This means that the terminal 3020 can not only verify the accuracy of the code phase CPC1 of the C / A code, but also verify the accuracy of the reception frequency fC1 when the code phase CPC1 has been calculated. do.

For this reason, the terminal 3020 can carry out positioning with more precision after verifying the precision of the code phase of positioning base code under the weak electric field with weak signal strength.

For example, as the number of GPS satellites 12a and the like being tracked increases, the terminal 3020 can reduce the code phase threshold β3 and use only a relatively high code phase CPC1 for positioning. have.

For this reason, the terminal 3020 can perform positioning using a relatively high code phase CPC1 under a weak electric field having a weak radio wave strength.

For example, the larger the number of GPS satellites 12a or the like whose signal strength (XPR) of the received C / A code is larger, the smaller the code phase threshold value β3 is. Only high precision code phase CPC1 can be used for positioning.

For this reason, the terminal 3020 can perform positioning using a relatively high code phase CPC1 under a weak electric field having a weak radio wave strength.

In addition, when the drift is, for example, within plus or minus (±) 50 hertz (Hz), the terminal 3020 makes the code phase threshold value β3 small, so that the code with relatively high accuracy is achieved. Only phase CPC1 can be used for positioning.

For this reason, the terminal 3020 can perform positioning using a relatively high code phase CPC1 under a weak electric field having a weak radio wave strength.

For example, as the elapsed integration time increases, the terminal 3020 can reduce the code phase threshold β3 and use only a relatively high code phase CPC1 for positioning.

For this reason, the terminal 3020 can perform positioning using a relatively high code phase CPC1 under a weak electric field having a weak radio wave strength.

In addition, since the terminal 3020 sets the code phase threshold value β3 smaller as the number of GPS satellites 12a and the like being tracked increases, the terminal 3020 can perform positioning using a highly accurate code phase CPC1.

In addition, since the terminal 3020 sets the code phase threshold β3 larger as the number of the GPS satellites 12a and the like being tracked decreases, the possibility of calculating the positioning position can be increased.

Although the above is the structure of the terminal 3020 which concerns on 3rd Embodiment, the operation example is demonstrated mainly using FIG. 48 below.

48 is a schematic flowchart showing an operation example of the terminal 3020.

First, the terminal 3020 receives the radio wave S1 and the like and calculates the measurement (step S301 of FIG. 47). This step S301 is an example of a phase calculation step.

Subsequently, the terminal 3020 stores the measurement (step S302).

Subsequently, the terminal 3020 determines whether or not the absolute value of the frequency difference between the current frequency fC1 and the previous frequency fC0 is equal to or less than the frequency threshold α3 (step S303).

In step S303, the terminal 3020 does not use the code phase CPC1 corresponding to the frequency difference determined not to be less than or equal to the frequency threshold value α3 (step S310). In other words, the positioning use code phase CPC1f is not used.

In contrast, in step S303, for the code phase CPC1 corresponding to the frequency difference determined as equal to or less than the frequency threshold α3, the corresponding prediction code phase CPCe is calculated (step S304). This step S304 is an example of the predictive phase calculation step.

Subsequently, the terminal 3020 maintains or changes the code phase threshold value β3 (step S305). This step S305 is an example of the phase difference tolerance range determination step.

Subsequently, the terminal 3020 determines whether the absolute value of the code phase difference between the code phase CPC1 and the predictive code phase CPCe is equal to or less than the threshold β3 (step S306). This step S306 is an example of a phase evaluation step. The terminal 3020 sets the code phase CPC1, which determines that the absolute value of the code phase difference is equal to or less than the threshold β3, to be the positioning use code phase CPC1f.

Subsequently, the terminal 3020 determines whether or not there are three or more positioning use code phases CPC1f (step S307).

In step S307, when the terminal 3020 determines that the positioning use code phase CPC1f is less than three, since positioning is impossible, it ends without positioning.

In contrast, in step S307, when the terminal 3020 determines that there are three or more positioning use code phases CPC1f, the terminal 3020 performs positioning using the positioning use code phases CPC1f (step S308). This step S308 is an example of the positioning step.

Subsequently, the terminal 3020 outputs the positioning position QC1 (see FIG. 43) (step S309).

By the above-described steps, the terminal 3020 can accurately perform positioning after verifying the accuracy of the phase of the positioning base code under a weak electric field having a weak signal strength.

This invention is not limited to each embodiment mentioned above.

Claims (22)

A phase calculating unit for correlating a predetermined replica positioning base code with a positioning base code from a predetermined source to calculate a current phase of the positioning base code; Prediction which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning, at the time of previous positioning. A phase calculator, A phase difference evaluator which determines whether or not a phase difference between the phase and the predicted phase calculated by the phase calculator is within a predetermined phase difference tolerance range; And a positioning unit for positioning a current position using the phase corresponding to the phase difference within the phase difference tolerance range. The method according to claim 1, The phase calculator calculates the phase by using a plurality of frequency series, The phase difference evaluation unit determines whether the phase difference between the phase and the predicted phase calculated using the frequency series having the largest signal strength of the positioning base code among the plurality of frequency sequences is within the phase difference tolerance range, Positioning device. The method according to claim 1, The phase calculating unit calculates the phase of the positioning base code by performing the correlation process of a predetermined replica positioning base code and the positioning base code from the source in at least one frequency sequence for each source; The positioning portion, A phase selector which selects the phase having the smallest phase difference for each of the source sources and selects the phase among the phases corresponding to the phase difference within the allowable phase difference range; A selection phase first evaluation unit for determining whether the signal strength of the selection phase is maximum; And a selection phase second evaluation unit that determines whether or not the number of times in the frequency series to which the selection phase belongs is within a prescribed number of times range which has been continuously within the phase difference allowable range, And positioning the current position using the selection phase when the determination result by the selection phase first evaluator and / or the determination result by the selection phase second evaluator is positive. The method according to claim 3, The said prediction phase calculation part is a positioning apparatus which is the said phase at the time of last positioning, and computes the said prediction phase using the said phase at the completion of the said correlation process. The method according to any one of claims 1 to 4, A reception frequency specifying unit specifying a reception frequency when receiving a radio wave carrying the positioning basic code; A frequency difference evaluation unit for determining whether or not a frequency difference between the reception frequency at the time of last positioning and the current reception frequency is within a predetermined frequency difference tolerance range; And a phase exclusion unit for excluding from the positioning the phase of the positioning basic code corresponding to the frequency difference outside the frequency difference tolerance range. The method according to any one of claims 2 to 4, A reception frequency specifying unit specifying a reception frequency when receiving a radio wave carrying the positioning basic code; A frequency difference evaluation unit for determining whether or not a frequency difference between the reception frequency at the time of last positioning and the current reception frequency is within a predetermined frequency difference tolerance range; A phase exclusion unit for excluding a phase of the positioning base code corresponding to the frequency difference outside the frequency difference tolerance range from positioning; The frequency series are separated from each other by a predetermined frequency interval, And the frequency difference tolerance range is defined by a threshold less than the frequency interval. The method according to claim 1, A phase difference tolerance range determining unit for determining the phase difference tolerance range based on the reception state of the positioning base code, And the phase difference evaluation unit determines whether or not the phase difference allowable range is within the determined range. The method according to claim 7, And the reception state includes the number of the originators of which the positioning device is receiving the positioning basic code. The method according to claim 7 or 8, And the reception state includes a signal strength of the positioning base code that the positioning device is receiving. The method according to any one of claims 7 to 9, And the reception state includes information indicating whether or not the drift of the reference clock of the positioning device is within a predefined drift allowable range. The method according to any one of claims 7 to 10, The said reception state is a positioning apparatus containing the information which shows the elapsed time after starting the said correlation process. The method according to any one of claims 7 to 11, The phase difference allowable range determining unit sets the phase difference allowable range to be narrower as the number of sources which the positioning device receives the positioning basic code increases. The positioning device sets the phase difference allowable range as the positioning device receives the positioning base code smaller as the number of sources. The method according to any one of claims 1 to 12, The source is a positioning device, SPS (Satellite Positioning System) satellite. A phase calculating step of performing a correlation process between a predetermined replica positioning base code and a positioning base code from a predetermined source to calculate a phase of the positioning base code; Prediction which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning, at the time of previous positioning. Phase output phase, A phase difference evaluation step of determining whether a phase difference between the phase and the predicted phase calculated in the phase calculating step is within a predetermined phase difference tolerance range; And a positioning step of positioning a current position using the phase corresponding to the phase difference within the phase difference tolerance. The method according to claim 14, The phase calculating step is a step of calculating a phase of a positioning base code by performing the correlation process of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, The positioning step, A phase selection step of selecting the phase having the minimum phase difference for each of the source sources among the phases corresponding to the phase difference within the allowable phase difference range, and setting it as a selection phase; A selection phase first evaluation step of determining whether the signal strength of the selection phase is maximum; Has a selection phase second evaluation step of judging whether or not said phase in said frequency series to which said selection phase belongs is within a prescribed number of predetermined ranges, said number being continuously within said phase difference tolerance range, And positioning the current position using the selection phase when the determination result by the selection phase first evaluation step and / or the determination result by the selection phase second evaluation step is positive. The method according to claim 14, A phase difference tolerance range determining step of determining the phase difference tolerance range based on the reception state of the positioning base code, The phase difference evaluation step is a step of determining whether or not within the determined phase difference tolerance range. On your computer, A phase calculating step of performing correlation processing between a predetermined replica positioning base code and a positioning base code from a predetermined source, and calculating a current phase of the positioning base code; Prediction which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning, at the time of previous positioning. Phase output phase, A phase difference evaluation step of determining whether a phase difference between the current phase and the prediction phase calculated in the phase calculation step is within a predetermined phase difference tolerance range; A positioning control program for executing a positioning step of positioning a current position using the phase corresponding to the phase difference within the phase difference tolerance. The method according to claim 17, The phase calculating step is a step of calculating a phase of a positioning base code by performing the correlation process of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, The positioning step, A phase selection step of selecting the phase having the minimum phase difference for each of the source sources among the phases corresponding to the phase difference within the allowable phase difference range, and setting it as a selection phase; A selection phase first evaluation step of determining whether the signal strength of the selection phase is maximum; Has a selection phase second evaluation step of judging whether or not said phase in said frequency series to which said selection phase belongs is within a prescribed number of predetermined ranges, said number being continuously within said phase difference tolerance range, And positioning the current position using the selection phase when the determination result by the selection phase first evaluation step and / or the determination result by the selection phase second evaluation step is positive. The method according to claim 17, Based on the reception state of the positioning base code, executing the phase difference tolerance determining step of determining the phase difference tolerance, And said phase difference evaluation step is a step of determining whether it is within said determined phase difference tolerance range. On your computer, A phase calculating step of performing correlation processing between a predetermined replica positioning base code and a positioning base code from a predetermined source, and calculating a current phase of the positioning base code; Prediction which calculates the prediction phase at the time of predicting the present phase based on the Doppler shift of the frequency of the electric wave carrying the positioning base code, and the elapsed time from the last positioning, at the time of previous positioning. Phase output phase, A phase difference evaluation step of determining whether a phase difference between the phase and the predicted phase calculated in the phase calculating step is within a predetermined phase difference tolerance range; And a positioning control program for executing a positioning step of positioning a current position by using the phase corresponding to the phase difference within the phase difference tolerance range. The method of claim 20, The phase calculating step is a step of calculating a phase of a positioning base code by performing the correlation process of a predetermined replica positioning base code and a positioning base code from the source in at least one frequency sequence for each source, The positioning step, A phase selection step of selecting the phase having the minimum phase difference for each of the source sources among the phases corresponding to the phase difference within the allowable phase difference range, and setting it as a selection phase; A selection phase first evaluation step of determining whether the signal strength of the selection phase is maximum; Has a selection phase second evaluation step of judging whether or not said phase in said frequency series to which said selection phase belongs is within a prescribed number of predetermined ranges, said number being continuously within said phase difference tolerance range, When the determination result by the selection phase first evaluation step and / or the determination result by the selection phase second evaluation step is positive, the step of positioning the current position using the selection phase, A computer-readable recording medium having recorded the positioning control program. The method of claim 20, Based on the reception state of the positioning base code, executing the phase difference tolerance determining step of determining the phase difference tolerance, And the phase difference evaluation step records the positioning control program which is a step of determining whether the phase difference tolerance is within the determined allowable phase difference range.

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